Stepmom get surprise cum in mouth when she helps with jerking to step son in share bed before fuck

My stepson came to me in the middle of the night and asked to lie down because my husband was on a business trip. I just asked him not to disturb me while I was reading a book. After a while he started to fidget and when I removed the blanket I was surprised that he was jerking off in my bed! I just wanted him to calm down faster and decided to help him cum. I didn't even notice how he was already fucking my mouth and suddenly cummed in it and a huge amount of sperm flowed right onto his penis. But I didn't cum! He has to fix that