Sex was usually referred to by metaphoric allusion in the old days because of hypocritical condemnation of it.

There are also of course honourable exceptions as Donne's
"License my roving hands, and let them go
Before, behind, between, above, below."

but then he drifts off into less direct metaphore.

And it's somewhat more likely to be productive, I feel, than asking "Can I stick my finger up your ..."