jumped on the grenade 

A female in a group or in a pair, that's not attractive. The one no one wants. But since she's not attractive and doesn't get the same attention as her hotter friends she gets jealous and turns into a cock block.

"I was hangin out with a buddy and took one for the team, jumped on the grenade to divert her attention."

jumped on the grenade by CaptainAmerica0329 September 25, 2013