Thanks @ficus and @snowbird for help with materials!
Alright, here we go! I translated this verse many years ago, and I didn’t make any notes as to my thought process, alas. So this is a good chance for me to go back over it and reassess.
The second couplet is a specially tricky one, as evidenced by the range of translations. This uncertainty extends as far back as the commentary, which offers a range of opinions.
I believe it is playing with innuendos, and thus hinting or winking at meanings that we can only guess. I think it’s quite likely that these were allusions that women of the time would have got, but which were designed to sneak under the radar of the menfolk, including quite possibly the monks who were gatekeepers of the texts. This is pure supposition, of course, but it’s a recurring theme in women’s literature.
In addition, several of the words have multiple possible readings or meanings. And most important of all, there is no obvious way to resolve the issues. Normally in a sentence, the sense of an uncertain word is clarified by its context. Here that is not the case.
Relevant context is supplied by Thig 1.1 Muttā, which shares a similar opening (“well freed!”), similar imagery (the mortar and pestle), and a similar theme: freedom from domestic life. I think the mortar and pestle allude to both kitchen drudgery and sex.
I’ll begin by discussing each of the terms and their possible readings.
- The opening phrase is printed in the PTS and Sinhalese editions as a vocative (“O one who is well freed!”) and in Burmese editions and apparently the commentary as nominative (“I am well freed!”).
- I follow Norman in taking it as nominative. As he says, if it had been vocative, it would have been used as the name of the nun.
-
musalassa: “of the pestle”. Glossed by the commentary as musalato (“from the pestle”) (i.e. genitive glossed as ablative). Norman’s updated edition prefers to read as genitive.
- all other translators follow the commentary here.
-
ahiriko is ascribed a number of meanings:
- from hiri as an adjective, the commentary says it refers to her “shameless [husband]” (mama sāmiko ahiriko nillajjo). Note that hiri is commonly used in hirikopina “private parts” i.e. genitals.
- Norman prefers the variant ahitako which he relates to the (otherwise unattested in Pali) ahita in the sense of “noxious, hostile”.
- Another possible derivation is from ahi “snake”, which is visually similar to the pestle, and chimes with “eel” in the next line.
- Most translators connect ahiriko with the husband, but Norman connects it with the pestle.
-
chattakaṁ means “sun-shade, parasol”. Chatta can also mean “student” (“one who carries the parasol”?).
- In dn27:14.2, ahicchattaka has the sense of a plant called “snake-parasol” i.e. a cobra’s hood, i.e. a mushroom, which Norman relies on for his “fungus”. This sense is well established for chattraka in Sanskrit. Given the domestic context, I suspect this is the likely meaning.
- The commentary explains that she didn’t like the fact that he made his living by making parasols, which seems a little small-minded. And the verse itself doesn’t hint at “making” parasols. Perhaps the sense is rather, “I couldn’t even bear to fall under his shadow”?
- The terms vāpi and vāti can be read a number of ways. The commentary mentions a variant for vāpi as vāti. So we could have any combination of the following.
-
vā api: “or”, perhaps in the sense of “and also”.
-
vā iti: “or” (close quote, i.e. the original ending of an independent verse?)
-
vāti: “to blow, emit a smell” (or conceivably, “weave”?).
-
iva iti or iva api: in the sense of “like”, “just as”.
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eva iti or eva api: “just”, “indeed”, “only”.
-
ukkhalikā is “pot” or “mortar”, the latter fitting well with “pestle”.
-
deḍḍubhaṁ is glossed in the commentary as udakasappa “water-snake” i.e. “eel”. The PTS edition reads rather daḷiddabhāvā (“state of poverty”).
Still with me? 
Now let’s look more closely at the commentary. This is a very quick and probably wrong rendering, may those of better Pali correct me!
Musalassāti musalato.
“of a pestle” means “from a pestle”.
Ayaṃ kira daliddabhāvena gihikāle sayameva musalakammaṃ karoti, tasmā evamāha.
She says this, it seems, because when she was living at home, due to her state of poverty, her chore was grinding with a pestle.
Ahiriko meti mama sāmiko ahiriko nillajjo, so mama na ruccatīti vacanaseso. Pakatiyāva kāmesu virattacittatāya kāmādhimuttānaṃ pavattiṃ jigucchantī vadati.
“My shameless [one]” means my husband who was shameless and unscrupulous, he was disliked by me (is what the rest of the words mean?). Since her mind was naturally inclined to dispassion regarding sensual pleasures, she speaks in disgust of an event leading to freedom from sensual desires.
Chattakaṃ vāpīti jīvitahetukena karīyamānaṃ chattakampi me na ruccatīti attho.
“And also making parasols” means: I did not like it that he was making parasols for a living.
Vā-saddo avuttasamuccayattho, tena peḷācaṅkoṭakādiṃ saṅgaṇhāti.
[Sorry, no idea!]
Veḷudaṇḍādīni gahetvā divase divase chattādīnaṃ karaṇavasena dukkhajīvitaṃ jigucchantī vadati.
Picking up bamboo sticks day in day out is a painful livelihood, she speaks in disgust at that.
‘‘Ahitako me vāto vātī’’ti keci vatvā ahitako jarāvaho gihikāle mama sarīre vāto vāyatīti atthaṃ vadanti.
Some adopt the reading “My bad (unbeneficial or “noxious”) wind blows”. The meaning is, “when living a home, my body emitted a bad, old (?) wind.”
Apare pana ‘‘ahitako paresaṃ duggandhataro ca mama sarīrato vāto vāyatī’’ti atthaṃ vadanti.
But some say the meaning is: “my body emitted a bad wind, smellier than others”.
Ukkhalikā me deḍḍubhaṃ vātīti me mama bhattapacanabhājanaṃ cirapārivāsikabhāvena aparisuddhatāya udakasappagandhaṃ vāyati, tato ahaṃ sādhumuttikāmhīti yojanā.
“my mortar wafts like an eel”: my rice-pot due to long disuse (?) and uncleanliness wafts like the smell of a water-snake. From that yoke I am well-freed.
Now are you still with me? Safe to say, no translation is very sure, and likely any translation will omit something and maybe miss the point entirely.
If you look for it, phallic or sexual imagery is everywhere here: the mortar and pestle, the snake and eel, the mushroom. I assume double-meanings are meant throughout.
There are a couple of details from the Vinaya that give us some background as to the beliefs about genitals that were prevalent in the day. According to the Vinaya (pli-tv-bu-vb-pj1:10.21.7) one of the causes of erections is wind. This could apply to the images of parasol being blown open or a mushroom sprouting. The Vinaya also has Mahapajapati complain about women’s genital odors, occasioning a rule about washing (Pacittiya 5).
Looking at the lines afresh, I am struck by the parallelism in the second couplet. Let’s assume that is the poetic intent.
Here’s a revised translation, but it is very much a sketch.
I’m well freed, well freed,
so very well-freed from the pestle!
My disgusting husband blew up like a mushroom,
my mortar blew like an eel.
