look up any word, like blumpkin:
 
1.
when you and your roomate are each having sex with different women, in a different room, where each roommate tries to make the most noise.
dude, i deffinitly won battle sacks last night
by Skynyrd09 September 28, 2009
 
2.
a homosexual sex game/ fraternity hazing ritual. two men stand facing each other while fully naked. both men grab their penises and hold them against their stomachs while swinging and hitting each other with their respective nut sacks. the first person to get an erection loses. traditionally in the homosexual sex game the loser has to give the winner a blowjob but the game can also determine who is bottom, who's cleaning up after, etc. as a hazing ritual this helps determine eligibility for a frat by separating the "chill dudes" from the "gay fags". origin of this game is unknown and it is difficult to determine who partakes in the game most often.
(homosexual version)" hey kevin, wanna play battle sack? loser has to clean the sheets!"

(hazing ritual)"the pledges played battle sack last night. everyone was a chill dude except for kevin. hes a gay fag bro"
by sue donime August 18, 2013