1. A Baseballer who pops off on the regular.
2. A person who sucks a lot of cock
1. Jim Thome may be really old, but he's still a bona fide dong masher
2. Trey: "I'm so horny"
Cory: "Call Penelope, that chick's been mashing dongs since 6th grade."
Trey: "True, she is quite a dong masher."