Now that summer is here, would BA Sam and Dean ever want to go swimming in a pool (with no one else there, of course)? I can imagine that’d be a bit scary for Sam but with Dean there it could be fun!
The moment Dean finds out that Sam can’t really swim (he hasn’t had a chance to practice since he was 10…), he’ll insist on starting small… like a sink. That way his little brother doesn’t go sinking to the bottom of the pool the second he gets in.
If they go swimming in a pool, they just have to make sure no one else is around to see the surprise borrower guest!