Nice! Too bad its not a son hearing that! But still hot, you can tell they are embarrassed!
Personally I prefer it when it's their daughter listening, knowing they're gonna be a fucked up slut with daddy issues just like their mom when they get older. It's extra fun when you can whisper real fucked up shit to their mom, about all the things you're going to do to her precious daughters, or might of already done behind her back, and have them not sure if you mean any of it or not, and still be unable to stop themselves from cumming on your dick 😂 that guilt of "I should be protecting my girls from this man, but I love his dick too much to care about keeping them safe"
But to each their own, they definitely looked more embarrassed after a while, as it went from a silly joke about their embarrassing mom, to the reality that they were listening to their mom get absolutely fucked, knowing her daughter/s can hear, and not caring.