Getting your next relationship set up before dumping your current S/O. Generally involves cheating (at least emotionally) on your current partner with the intended future partner. Refers to playing on the monkeybars, where you don't let go of the first bar until you've grabbed on the second.
Bill: "Well, your brother just sent the Save The Dates for his third marriage - they haven't even finalized the divorce yet!"
Joe: "Yeah, the monkey branching SOB did the same for his second marriage as well - all his relationships 'overlap,' if ya know what I mean."
OR
Joe: "Sue and I decided to try an open relationship."
Bill: "I dunno, sounds like she's monkey branching to her *next* relationship."
When your poop is so large that it breaks the surface tension of the water from below. (similar in concept to how a whale or a submarine “breaches” the water)
when a girl already has a boyfriend but she gives her number to guys that she meets and flirts as if she were single. she's basically branching off from her boyfriend and establishing backups.
yo dude I saw your girl at starbucks giving her number to some guy. I don't think she saw me. it looks like she's monkey branching, you should dump her.