When your having anal sex and you slip your dick through a slice of American cheese and continue to rupture her anus, hence the name, cracking the bun off the cheese.
An example for Cracking the bun off the cheese:
“Yeah Susan, Earl was taking me down to pound town and then he grabbed a slice of American cheese and stuck it in the wrong hole and he cracked the bun off the cheese.”
Someone who jumps from one relationship immediately into another one.
Serial monogamists can not stand to be alone and often suffer from vast commitment and insecurity issues.
Because they jump into relationships immediately after the previous one has ended, serial monogamists typically don't take the time to reflect on their behavior or why their previous relationships failed; thus, they end up making the same relationship mistakes over and over again.
Person 1: Damn, Dustin already has a new girlfriend?! It's only been two weeks since he broke up with his fiance! I think he's a sociopath.