When a man is trying to reel in a very large fish, gets VERY excited, and makes very loud noises similar to an orgasm.
Dude! Did you see that video, 'Giant 600 Pound Goliath Bass breaks rod'?
Yes! That was hilarious! He totally had a fishgasm!
When someone catches a large male salmon, swueezes the sperm onto their faces, and calls it a day.
John-your skin is so smooth, what do you use?
Paul-I get a fishgasm every morning