You only get disciplined during sex if you want to. Drinking drives people to sex, where as school drives people to drink. Sex relieves stress. School is the cause of stress. After sex you feel like you have accomplished something.
Sex is cheaper.
Even if you have to pay for a hooker, it is still cheaper than paying thousands of dollars in tuition. At least you have a choice whether or not you want to have sex. At school your teachers screw you regardless.