Hi, I live in France but originally from Spain. I hope to write correctly in English.
We went to my parents home on the last Christmas. Since my brother came too so that we could have a nice time with all the family together there weren’t much rooms to share so my son, who is 13, and me had to share bed in one room.
One morning, my son woke up with a hard on, I could notice it but didn’t said anything at all since its something embarrassing. My son run to the tiny bathroom (we have 2 bathrooms at my parents house, one huge with tube and another one tiny) trying to hide from me the obvious.
Then, my mom needed to pee and the huge bathroom was full with people so she decided to use the tiny one with the surprise on opening the door of finding my son standing up naked with his underpants at his ankles and masturbating. He didn’t noticed at all the door opening since there was lot of noise at that moment of the morning with everybody waking up and the bathroom next door with lot of people.
I am very open minded so I don’t care if my son does masturbates and also is my mother, but despite she is modern it was a shock for her to found her grandson masturbating so she got shocked and had no reaction for 2-3 seconds and then she shout “OOOOhhhhhhh!”. My brother, who was at the other bath entrance stepped next to the tiny bathroom and realized what just happened, he was the one who explained me later.
My son did realized he was being watched when my mother shouted so he tried to hide his guilty without succeeding very well and then my mother looked away and walked to the dinner room while my brother looked at my son smiling and my son closed the door.
It took a long time for him to go out of the bath, for nearly 30 minutes, I think because he was too ashamed, I tried to talk with him later but I think this only made it worst and also there were some jokes around all of it made to my mother and him during all the Christmas. He finally laughed at it with all so I think he has not got a trauma and the jokes worked fine.