FUN! Brings back memories when I did this as a kid and was told if I didn't stop, my eyes would stay like that. My siblings even tried to sneak up behind me to slap me on the back, as rumor was, slapping one's back when looking cross-eyed would make the eyes stay like that. LOL!
@tctime I remember that saying about your eyes staying that way too but I've never heard about the back slapping part.