I could never leg in. It seemed like my legs were too thick, or maybe my joints just too stiff, but I couldn't get myself bent around like that. However, I got real good at catching leg riders. I would often bait them by raising my hip (with my elbow already in tight) to get them to try. There was a LOT of pleasure in bringing that leg up and stuffing it into their chest.
Anyone who puts a leg in over a tucked in arm deserves what he gets.