This isn't necessarily a great baseball moment, but was really funny.
This was in about 90 or 91. We were playing some directional Louisiana school and their big ol' first baseman had caught crotch critters from somewhere he shouldn't have been. He got to itching and scratching pretty bad, I mean he was digging. Well, every time he did, we'd all yell, "SCRATCH SCRATCH SCRATCH."
It took a while, but he finally caught on. He got to laughing. When the itch would come on, he'd squirm and try not to scratch. We'd yell, "Don't... Don't do it." He'd smile and then laugh and start scratching and we'd all yell, "SCRATCH SCRATCH SCRATCH"