To be swollen; to be fucking jacked. Gaining so much mass that girls offer ass. The definition of having guns for buns. Flex for sex? You don't even need to flex to get sex. Remember, Muscles, never steamers.
The term was originally used in reference to being "all-in" on Tampa Bay Buccaneersrunning back Doug Martin, who is known as the muscle hamster. However, the term sounds much more like putting on a condom.