It is a normal evening. Only Sam and Dean in the Impala in the middle of the road. The brothers as always--
"You are an idiot!" yells Sam.
"No, you are!"
"Me? And how's that, Dean? I was the one who told you it would finish that way!"
"Yeah, but who would have listened to the idiot?"
"Dean--"
Easy, boys. What are arguing about?
Brothers look at each other and for a moment there is a silence in the car. Finally Dean decides to explain it.
"I don't know. You said that we were as always. Idiots"
Excuse me? What have you just said?
But it is Sam who's talking this time.
"Look, I think we're arguing about this whole deal with crossroad demon you've made."
"Again? Dude, we've been discussing this like hundreds times already. No I think we are arguing about the fact that you didn't buy me an extra pie"
"Man, if you keep eating so many pies, you'll find it difficult to get out of the car soon"
"So I'm fat now? I am fat? Seriously?! Look at that fat chick--"
Hey! Who's fat?!
"-- that is what I call fat, Sam!"
I'm not fat! I'm just well-built.
"Dean--"
Size 12 is not fat!
"And just look at her hair! What's happened? The vacuum cleaner sucked in your hair and spitted it out?!!"

OK, that's it.
And in this exact moment Impala stops in the middle of the road with creak of the breaks.
"Dude!?"
Dean gets out of the car without a word, stands in front of the windshield and starts taking his clothes off--
"Wha..? No!"
-- taking his clothes off, until--
"Sam!? A little help here!"
--until finally the only piece of clothes Dean is wearing are pink boxers with blue butterflies on them.
"Those are not my boxers!" Dean tries to lie, but he feels a sudden urge to dance Macarena.
So he is slowly moving in direction of the gay bar which happens to be around the corner.
"I'm not going! You can't make me!" Dean tries to scream, but it's not easy to dance Macarena and walk and scream at least not when the branches of the trees are spanking you in the face--
"Ow!"
--in the abs, in the stomach… And everywhere below.
"Owfphhh"

When he finally reaches the bar and stands in the door, the people inside are suddenly in silent like they have never seen the man in the pink boxers before. The silence is broken by Dean's baritone singing "My heart will go on"
"Sonofa… Every night in my dreams, I see you, I feel you…"
And when Dean is thinking that nothing worse could happen, after a few lines of the lyric, he sees Jo--
"NO! Near, far, wherever you are, I believe that the heart does go on…"
--with a cell phone camera. And Dean is singing along.

---

That night was momentous. Some remember the guy in the pink boxers, some saw the warming not to drink too much after putting on pink boxers. And older Winchester finally learned not to mess with a woman with PMS.