https://www.tumblr.com/marginofthought/809510511942287360/i-know-that-its-hinted-at-that-sam-finds-the
I initially assumed Sam was faking his grossed out reaction cause there was other people in the room with them.
Then I remembered that Season 12 episode where Sam points out Dean had not changed his boxers in 4 days…
Link
Yeah remember this? I mean Dean is kinda disgusting so I don't think it's too far-fetched to think that Dean doesn't wash nearly enough even in the bunker. Dean is probably nose-blind to his own smell.
Also fun fact here are his reaction to siren/guts (aka disgusting and smelly) in Dean's hair next to Dean potentially giving Sam a whiff of his unwashed dick and balls.













