Life drawing nude modelling erections

Has anyone ever had an erection.while nude modelling?
I have be doing this for a while now, a very progressive girls school allows seniorsnin art class to have models. I was ok for a while but a seriously hot bunch of girls rigjt up the front where staring and whispering, giggling and i could hear tjeir comments. I slowly began getting a boner.this made it worse. Quiet hysteria was taking hold..i was standing in front of half a dozen girls , the rest of the class watching. I tried to stop but my massive cock.just grew and grew until i had a throbbing boner. The class went into melt down. No teacher in the room. It was such a turn on. I had to pretend i was emmbarrassed and be awkward. I only made it worse.[image removed by staff]