When a man and a woman are having sexual relations in the missionary position, and the man fits his entire scrotum into the woman's vagina, and then slapping his penis onto the top of the woman's pubic area while mimicing the sound of a large bell.
"Did you hear that Ben Reilly gave that girl a bats in the belfry? BONGGGGGG BONGGGGGGG!"
by Babyballs October 05, 2006
An antiquated term for insanity, madness. Belfry: the top of a bell tower on a church, where the bell is housed. Often infested with bats, who enjoy the darkness and seclusion of the place.
She's got bats in the belfry, sqirrels in the attic, owls up in the loft. She's apeshit, bughouse, batty, mad as a march hare.
by gramaticon August 02, 2005