Dean didn't remember when Cas started sharing his bed. It had just started and continued on. Dean would never tell Cas his real feeling because of the fear of Cas not feeling the same way and feeling disgusted. Every morning, Dean would wake up and see Cas asleep and feel disgusted by himself. Dean, who was known for having sex with every hot girl he met, wanted to be with a boy. And what were the chances of Castiel, a fallen angel, wanting to be with Dean. So every morning, Dean just went on with his day, trying to block out the thoughts about dating Cas.
One warm summer morning, Dean woke up to Castiel looking at him. Dean just laid there and stared back at Castiel. Then Cas moved closer to Dean and Dean tensed up, not fully sure of what was happening. Then Cas gently put his lips on Dean's lips. Dean made the kiss more passionate and he put his hands under Cas' shirt. Cas tensed up under the Dean's cold hands. Then Castiel hungrily pulls off Dean's shirt. Just as Dean is about take off Cas' shirt, they hear Sam call them, saying he found a job. They both get dressed without looking at each other. Dean is wondering what the hell just happened and he regrets it, thinking that Cas is disgusted. They work the case without too much contact. Little does Dean know Castiel was just waiting till they got back to the bunker to have some more fun and romance.