We have only had the pleasure of meeting one Asian couple, who were Thai. He had a small penis and was a lot smaller physically, though we did get along very well on a social level... he was quite submissive but the conversation was very friendly and relaxed. But he was also very aware of his place. We sat with his wife and he sat across, serving takes as we got to know her better. I'll keep the scene brief, but it was a very charged atmosphere. At one point we decided we wanted to have her so got up and went to the bedroom with her. She told him to go put the light on and get the bed ready. When we went in there I ordered him to undress and we relaxed on the bed and laughed at his size and weakness. It has been leading to this and we all knew we were ready to explore this, having emailed and chatted on the phone previously. He was ordered to remain in the doorway watching as we three got much more intimate. We humiliated him through his wife as he got a running commentary of everything, interspersed with comments on his prowess. He still had to serve in little ways, to keep him involved, which is what we enjoy most. To fully feel part of the experience.
As it got hotter he was told to go get a fan and a towel, then to come kneel by the bed. He got to watch closely as his wife was thoroughly taken. He was given permission to masturbate, after begging and kissing penis and pussy appropriately. Then he was allowed to cum, if he came in his hand and licked it up. At the end he had to clean his wife thoroughly from our sweaty sex session. After we lounged on the bed as he served us...
Sadly we haven't been able to go much further, but we adore the kind of relationships that can be built in this. Of course a couple is a little more unusual, but it works for us