When a man fucks a woman in the vagina and finishes, causing some semen to leak out from the vagina onto the crotch/pelvic area as a sticky white frothy substance.
The act of two or more close, straight, male friends, further strengthening a bond of friendship by either simultaneouslyhaving sex with the same woman or having sex with the same woman one after the other.
Clint: Hey guys, we should become cum brothers!
Zack: Yeah! Sounds great, bro! It'll bring us even closer together!
Troy: Yeah! I'll call my sex-crazy, ex-girlfriend, Jessica, she'll be down!
Two men, who have symbolically demonstrated the strength of their emotional bond by masturbating, while staring into each other’s eyes, until each of them ejaculates into an open palm. The ritual is completed when the men firmly shake one another’s cummy hand. When the semen is mixed, the men are cum brothers.
Nigel and Pierre were never very close, as far as anyone could tell. That is until, the two found themselves on the same team during a summer camp trust exercise. The two became close, but no one would have guessed that by the end of the week, the two would be Cum Brothers.
Where two straight male homo-sapiens touch tips of the penis, they then ejaculate simultaneously and combine fluid of , then making a part of them, a part of you. Therefore you are brothers.
Me: Yo, Addison, Ragsdale. We have got to become better friends, you know what would make us so close, DUDE! We should become Cum Brothers.
Homo-sapien Of the Given Birth Name Addison: Don't you think that is a littlle... Gay
Me: No, why would it be...