When taking gymnastics at school we were made to wear cotton gym slips only,when doing jumping up and down and running on the spot the friction of the material rubbing against my cock would give me an hard on which was impossible to hide from the well endowed female gym mistress who wore a simple sports bra and tight fitting pants,despite the pain she would make us do the jumping over the wooden horse landing on our balls in the process revelling no doubt in the sight of our young but strong erections,to try and get around this problem I tried to put tight fitting underpants on first which were banned,you had to wear just the gym slip,she must have twigged because one day I was summoned to evening detention and to appear in only my shorts,the reason was apparent as she had her cane with her that evening to further my ordeal,I was told to bend over the gymnasian wooden horse which I did and she pulled down my shorts sharply catching my erect state pushing against the leather material of the horse,what followed were 20 strokes of the cane which made me hard as rock and she was loving every minute of it and told me next time I would get double,she really had it in for me and would find the slightest thing to punish me,all of this was followed in private by me having to wank off to relieve myself,to see her tits moving as she laid on the strokes was really something and to this day I have never had such hard erections as back then,this is why these videos really are a turn on for me.