One of my daughter's good friends is living with us for her first semester of university.
She is staying with us because her room mate decided at the last minute to postpone his semester and she could not afford the rent by herself.
Today I got back home from work early and thought the house was empty until I started hearing soft moaning and deep breathing coming from Kim's room at the end of the hall. I knew what she was doing and did not want to interrupt her. I got hard in no time as I listened for a few seconds.
I then felt guilty and went back to the garage door and closed it loudly and called out to see if somebody was home to which she replied. She left an hour later for her class and as soon as she was out the door, my hand found my painfully hard penis and I started to masturbate.
This mental image will be with me for a long long time I hope.