I was giving my boyfriend a bj the other day and at first he was really hard, but eventually he got pretty soft and basically had to finish himself. I've done it plenty of times before with him, and I wasn't doing anything different, and he's normally hard the whole time. He didn't say that I did anything bad, but that he was pretty tired. I think in the past it's also been a bit of a problem when he was tired. Is this normal? I don't mind, but I think he feels a bit embarrassed when this happens.