Unexpected

I was in my early 20's at the time and over at my girlfriend's mother's home. My girlfriend was working late and her mother and I were chatting in the kitchen preparing some snacks for her when she came home. I had been over often and enjoyed her mom's hospitality. Her mother accidentally spilled some chocolate sauce over the crotch of my pants. She felt bad and without thinking started using a wet cloth to wipe off the stain. Her wiping gave me an erection which I tried to hide by wriggling away in embarrassment. She was a blonde big breasted 50 yr old and feeling her so close made it feel so intimate. She then suggested I take off my pants so she could wash them. I was so flustered I pulled them down and my hard cock popped out of my underwear. She gasped and said poor boy what have I done ? She then went down on her knees and took my cock in her mouth. I was so aroused a few sucks on my cock and I exploded in her mouth. She took it all and gulped it down. She smiled at me and said everything is better now as she took my pants to the wash. I ended up wearing a spare pair of jogging pants I had left there previously.