I have the PERFECT solution that I use EVERY gym class. Wanna know what it is??DONT SHOWER!!
oh no no no no no! shower! you'll smell bad! and don't say "well i'll just put on deodorant", because to drown it out, you'll have to swim in the spray ons, and a vast majority of my school hates the smell of too much axe or tag
oh but if you are so scared that you cant step foot in a shower without getting a boner, then i guess jack off before school and you're boner will not appear