Hmm - well, it certainly mattered to me at the time. Slightly absent minded really. Possibly I was more like 7. I remember being very embarassed afterwards - that might have been a result of my mum telling me how stupid I was rather than a gut reaction, though. Ah well, haven't done it since 
Incidentally, the first result on a google image search for "penis in shorts" (I'm sane, really) is rather interesting.

Incidentally, the first result on a google image search for "penis in shorts" (I'm sane, really) is rather interesting.