silent sex 

what married people do when they're too cheap to get a second hotel room, and have to have sex with two sleeping 7 year olds in the next bed. Usually accompanied by silent shushing faces, muffled giggles and careful movements so as not to make the bed creak. Culminates in silent grimaces during climax.

Stan and Diane got a great hotel in Maui for their 10th anniversary, but ending up having to have silent sex, since it was too pricey to get a second room for the twins

silent sex by Veranda Collingwood February 26, 2011

Silent Submarine Sex

The act of performing a sexual act while one or more people are in the same room.
Usual occurs at drunken parties and gatherings.

Dude, I Silent Submarine Sexed Sarah last week after you passed out on the couch,
or
Me and Sarah had Silent Submarine Sex on the floor while you guys were playing monopoly.

Silent Submarine Sex by Jordo.. March 16, 2006

silent movie sex 

When you and your parent have to apply duck tape over your mouths during sex because the kids are in the house and you don’t want to be loud

Baby, we gotta have silent movie sex tonight. The kids are awake

silent movie sex by MsMiraya February 21, 2018