When a group of guys go to mack on a group of girls, the guy who jumps on the grenade is the guy who goes after the fat chick in the group to clear the way for his friends to go after the hot ones. Usually guys take turns
"Man I ain't jumping on the grenade this timn. I did it last time"
Having a very long drawn-out romance in which you break up and get back together on a regular basis because the couple in question thinks they're soulmates. Derives from the popular television show Dawson's Creek
"Man Heidi and Brad are so dawson and joey. I think this is the fifth time they've broken up this month