straight-faced pervert

Someone who is able to do perverted things while keeping a straight face.

Him: Do you wanna use the BDSM kit and the dildo tonight?
Her: w-what? Don't say such perverted things with a straight face!
Him: What do you mean?
Her: You're acting like such a Straight-faced Pervert!

by Weeabob November 28, 2016