Three men and baby consists of four people in a sexual act, usually involving three men and one girl. One of said participants gives the girl a dirty sanchez while the other cums on her chest. The third person then places pubes he/she has collected over the course of a couple weeks and places them on said chest. Once complete, the three people all yell three men and a baby.
Dude I was at this party the other night and this chick got gangbanged and given the three men and a baby.