1. noun. Similar to a threesome, but as the title implies, involving only two people. It is not the same as sex...it is wilder; with the intensity of a threesome.
2. Can be used as a verb when appropriate. Implies the act of having wild sex.
1. "I had a twosome last night with some exotic chick. I'm exhausted."
"Twosome? You mean you had sex?"
"Naw, man. Twosomes are hotter!"
2. "Dude, I wanna take that chick home and twosome her!"