1.
Figuratively meaning light, easy, care-free play. Derived from pillow-fight-like play with beanbags. Mostly used to indicate the opposite. i.e. "ain't beanbag" means rough, cut-throat play - especially in
competition. This is used by a more mature audience.
2. Uncommonly used term for testicles and scrotum. It doesn't take a genius or
urban dictionary to figure out that connection.