Heart Flips 

The equivalent to butterflies in the stomach scenario, but much more accurate. It literally doesn't feel like a pounding heart, but more like the heart is doing gymnastics at high speed.
Flipping occurs in situations such as:

-thinking about/being with someone you like
-infatuation
-nervousness
-fear
-emotion overload
-being scared

This is also used as a noun ie. heart flippage

"Yeah, when I was with him, I just had these heart flips."

"I didn't even think it would but there was just this random heart flippage, and suddenly yeah, I liked her."

"She says she loves him because she always has heart flips, but I think it's just infatuation there."

Heart Flips by Dalisay November 20, 2009