Girlfriend's mom

I dated a girl once whose mother was 42, single and sexually active. She had a boyfriend too and on weekends sometimes I would be fucking my girlfriend in her room while mom's boyfriend was fucking her just next door. Sometimes I would hear the headboard banging against the wall of how hard mom was probably getting fucked, it was hot and it used to turn me on a lot. The mom was sexy too, she wasnt that young, but she was thin, had a nice ass and dressed sexy I can just imagine the nasty things her boyfriend was doing to her in bed. I fucked my own girlfriend thinking about her mother many times!