"Wriggling" is a pretty standard translation of 藻掻く but in English it's associated with worms. WORMS! 🪱 "Undulating" is much nicer. e.g. A pussy doesn't wriggle, it undulates or ripples, or it convulses around his cock.
Sometimes a woman's skin may be described as 白魚. This is sexy in the original cultural and linguistic context. In many English-speaking cultures, fish are used for negative comparisons. Something like translucent or dewy would be an appropriate equivalent.
On the other hand, don't throw in porny words where there shouldn't be any; if your heroine is a shy virgin and the source text is using coy words like あそこ, don't have her shouting FUCK MY TIGHT LITTLE PUSSY in English.