We all washed in a farmers pond back in the day,loaded bales of hay on the wagon all felt good to cool down and to get washed we alway soap and shampoo.
I live in the countryside and men usualy wash naked outdoors in the river, or at a cistern drilled into the ground from which you draw buckets of water. In summertimes it could be fun, but in wintertime it is brutal. You ain't got to be ashamed because you are a man. And men usualy don't wear underware because you are a man and you've nothing to be ashamed about, only women dress underware.