Up goes the maiden's heels

In Beaumont and Fletcher's burlesque Knight of the Burning Pestle, Mr Merrythought sings:

With hey trixy terlery-whiskin
The world it runs on wheels;
When the young man's ______
Up goes the maiden's heels.

Presumably the missing word rhymes with whiskin. I thought of friskin', and so did whoever wrote in the margin of one edition reproduced in google books, but that's not obscene enough to be replaced with dashes.

Any ideas?

Several sources give a bawdier version:

When the young man's prick's in
Up goes the maiden's heels.

The rhyming word is given as whiksin or whicksin instead of whiskin.