When a girl gets cramps in her stomach (technically in her ovaries) after having intense sexual intercourse but without achieving orgasm. It is NOT the cramps a girl gets when she is on her period. Blue belly is basically the female version of blue balls, although unlike blue balls, it can only happen during intercourse, as opposed to masturbation. It's also less common than blue balls, but the pain can still be quite intense and can last for up to several hours.
Jacob: Hey baby, time to wake up.

Alissa: Ohhh... I don't feel good. My stomach really hurts.

Jacob: Do you need me to call a doctor?

Alissa: No, it's just that when we had sex last night, I was so close but then you pulled out anyway like an asshole... and so I just lay awake all night with blue belly.
by Michael Hammond May 4, 2013
A small lizard found in sunny areas. Adults have bright blue scales on their stomachs. Also called the western fence lizard.
I saw a blue belly on my last camping trip!
by newgnella June 2, 2018
Aches in the pelvic region without period. Vasocongestion (blue balls) for women. Women's genitals also become engorged with blood during sexual arousal and, like their male counterparts, women can experience pelvic heaviness and aching if they do not reach orgasm.
I was messing with my girlfriend and before i could get her to orgasm her mom came home so we stopped. The next day she was complaining that she got blue belly.
by vman1212 October 18, 2008
when someone gets shot and dies
dame that mother fucker just got blue-bellyed
by boomer jinkins April 11, 2011
A phrase used for when you notice you've been working at Best Buy too long, and you come home after every shift to find a piece of blue lint lodged in your navel.
Mother: What's that blue thing sticking out of your belly button, son?
Son: Ah, that's the dreaded blue belly button I always get now from working at Best Buy too long.
by Commodore Barry July 17, 2009