When a married woman has sex with her lover, boyfriend or date commonly referred to as a Bull. When a woman has sex with someone other than her husband, usually a larger virile or well hung male partner. Such a partner is referred to as her Bull.
The act of finding the fattest woman to fuck: fuck her doggy-style and wrap your arms around her if you can; then whisper in her ear "you are the fattest bitch that I have ever fucked"; and hold on for the ride.
The woman is on all fours in doggie position. The man is on his knees, sitting upright, penetrating, reaching around to massage her genitals in one hand and waiving the other in the air.