Asian culture

I am curious about the Asian culture and mindset. Especially those of Chinese descent. For over the past 15 to 16 years, I have gone to this legit Asian massage place run by this older married couple. Both are probably in there 50s he might be in B in his 60s. I have gotten legit massages from both. Both have seen me wear men’s thongs and women’s panties. They are both very friendly. All massages have been legit massage. Except for over the past two years or so with the husband, he has allowed me to rub his crotch area with either my elbow, my knee or my foot depending on the position I am in when he is rubbing me down. He doesn’t touch my cock. He does not touch my balls. He does not touch my hole. But he does get very close from time to time. If I try to ru rub his crotch with my hand he will pull away. But then I can go right back to using my foot or my elbow or my knee to rub on his crotch. I am curious about why he’s letting me go sort of 50% but not to 75%