to Dogbreath150 :Yeah happened to me once with my step dad. He saw my erection and said oh you like it you little p**** and gave me additional straps. Personally I feel he enjoyed humiliating me and pulling my underwear down.
to Gazzpacho :When I was getting a thrashing from the old man back in the day I'd get hard as a steel spike - he thrashed me harder because of that!!!!