I have had a few intact males and not one of them would ever think of doing what you describe. It is NOT something that should be laughed off and it certainly isn't normal. I am not saying that you need to take him to vet to find a medical reason why it happened, you need to see a person about training you to train your dog.
My intact males don't get invited on the bed very often and certainly not at the young age of 1 1/2 years old. When they do get invited on the bed, they are not very comfortable with being up there because that is not their position. They get themselves off pretty quickly. This is not to say that they are uncomfortable about being on the furnature- they are very comfortable about that.
This is the age that dogs see if they can move up their position in the house. If they think they deserve that higher position, you are going to be in a world of hurt and I do mean literally. I love my dogs dearly, but I make it very plain that they are lower then dirt. If there is any attempt to rise above dirt, I remind them that it is MY house and I make the rules, not them.
My husband's dog is a 3 year old intact bitch. He spoils her and she knows she is spoilt, but she knows there is a line and she does NOT cross it. He does take her to bed and she sleeps on the bed until I get up there. I just have to walk into the room and she is getting off the bed. My husband thinks it is amazing she does it. I tell him that she knows her place is the floor and she accepts that without question.