(v) To have sex. Pron "Shtoop" ("oo" as in "book") This word is of Yiddish origin. Of note, one never schtups someone else...two people schtup (together).
"What are they doing up there?" "I think they're schtupping!"
Yiddish for to have sex with, ie to fuck, to screw.
They were schtupping while people were in the same room!
I could really use a good schtup.