It usually means he needs to clean himself. He might be sweaty, dirty, or simply wants to freshen up. This doesn't necessarily imply anything about his intentions towards you.
Here are some possible interpretations:
- He is simply stating his intention: He may be telling you this as a matter-of-fact statement and doesn't expect you to wait around for him.
- He is trying to end the interaction: He might want some time alone or needs to change into more comfortable clothes.
- He is being polite: He might be letting you know he will be unavailable for a while.
It's important to remember that context is key when interpreting someone's actions. If you're unsure, you can always ask him for clarification.