In the new episode where Francine tries to spice things up in the bedroom there are two scenes.
The first has Francine being taken into the woods tied up by Stan because he thinks she's a deviant
The second happens when Roger is convincing Stan he is in the wrong and they sing a funny song about how everyone has a kink of some sort and during this we see Toshis' (Asian kid) mother bound and suspended by her husband being whipped during the song
yep, saw that the other night, new episode I think. but yeah, Toshi's parents showed up in the background on that one, kind of ironic since I don't think Toshi was even in that episode
my bad