How can you tell the sex of a dwarf hamster?

You just said in your question its male so wouldn't that be the answer? ;)

unlike the syrain hamster the dwarf hamster is very small, when the syrian hamster i larger and thicker and also with a lighter coulour.twsiter1998gobstoper88

if it poops

it is really easy, they are tiny, about the size of an acorn or smaller and they are pink if they're less than a week old.