I don't even know where to start with this. First, it was not an accident. This is one of the things his mom is mad about. So I would be very careful about claiming that you didn't mean to do it. Why does his mom now not trust your mom? Did they talk about this? You say that you are fourteen and this is not that big a deal. Well it is. If for no other reason than you would like to keep seeing your boyfriend and this made his mom mad. But the bigger reason that it has your boyfriend's mom upset is because this is an indication that the two of you are sexually active. If that is that the case then it is definitely her concern. You need to consider the position you put your boyfriend in by doing this. All of us do things that we think is cute or funny at the time and they turn around and backfire of us. It sounds like this is one of those times. I hope things work out with your boyfriend, you and his mom. You probably need to be apologetic toward his mom and not present the attitude of “it’s no big deal.”