Lyric discussion by couldBanyone 

Cover art for Girl O'Clock lyrics by Dismemberment Plan, The

Good effort exeter, but if you checked the lyric sheet you would know this line is correct:

"when it's there, inside you day or night, you know it's girl o-clock" (perhaps you heard a different version)

Obviously about a sex-crazed maniac. I think it is in jest, especially the stuttering, maniacally over-the-top vocals. The "tick tock you dont stop" section makes me cringe cause its so corny.