You Can't go to School Naked by Dianne Billstrom, illustrated by Dn Kilpatrick, III

From chapters.ca:
Lots of kids like to run around naked and here's a funny book to remind them why it's best to keep their clothes on, particularly at school. Just think about it... could you go down the slide? Steal second base? This little guy's parents warn him of many dangers he'd face if he went to school without clothes on, and eventually he sees their point. But if he has to wear something, it's going to be what he chooses (and it's only slightly better than going naked). Kids will giggle and squirm at the silly scenarios this little guy imagines and cheer his unique solution.