a large group of butterflies
Look at that flutter of butterflies!
British term for placing a bet on something.
"Fancy a flutter on the 3.00 Derby, Fred? I've got a tip that Elizabeth Green Massacre's going to walk it."
"The one with three legs, you mean? Go on then."
That feeling in the pit of your stomach when someone you really really really really like touches you in some way
"Stacy got flutters when she was dancing with Jim"
The slapping of the male testicles against the woman's pleasure zone during sexual intercourse.
- In other words when you're having sex and the guys balls slap against the woman
'My balls are fluttering'
'His balls fluttered'
'He fluttered me'