Dean is openly Bi, and it's the bane of Sam's existence.

They'll be on a hunt, and suddenly their in a bar and Dean's hitting on everyone within a five mile radius.

The same thing would happen whenever they were talking to witnesses or researching.

The only thing Sam was happy about was the fact that Dean was Happy, and that was good enough for him.

That being said Dean was currently and relentlessly flirting with the bartender even though they should be going.