With much thanks to my new found friend Skink (from The Worst Of Perth blog) who has held my tiny monkeypaw and walked me over to Roger's Profanisaurus, i am able to share some more donkey references with you.
Not sure why the donkey features so strongly in sexual innuendo and terminology aside from the fact that they have huge penises. Perhaps that is all it is. Which just goes to prove, that size does matter:)
donkey kisser (n.) female She who does not kiss well; that girl who kisses like a donkey chewing an apple.
donkey rigged (adj.) Possessing a large penis.
BTW, if you google donkey penis images, it brings up lots of photos of the edible delicacy of cooked donkey penis. I can't stomach the pictures but you fill your boots.