Mortar is like a woman's fanny; the more you play with it, the wetter it gets.
My tutor just said this quote of 2k18^^^
Pontypool is rough.
Alright listen up, buttercup. This joke is using a "mortar," which is like, cement stuff, and comparing it to a lady's... well, you know. The joke is that the more you mess with either of them, the wetter they get. It's kinda nasty but also kinda funny, in a stupid way. And you, my friend, are very, very stupid.