I don't understand the masturbation aspect. Was Chen in love with himself (or body in love with soul???)? Or just a sensual man who needed to feel pleasure constantly? Who asked for the jade suit: the pò or the hún? Or were they in agreement about it (why, if the main goal of the hún is to leave for heaven/hell?), but as you say, the jade suit worked too well? Not clear, I think.
In my most original draft, Chen was supposedly into himself (narcissist) and have the suit made to preserve himself .
But I have since changed that to him being a guy who dreads the idea of his body rotting away (you know, like Gilgamesh). The hun and po may be parts of Chen, but they do not really represent Chen. At this point, they are effectively two separate things and don't really know Chen as well as they believe.
lack of familiarity with the jade-suit legend…!
Yeah, it's rather obscure. But we got Wiki.
ETA: or is Chen-body refusing to die because he still wants to experience sexual pleasure?
Well, the po can be defined as the animal soul of a man (as opposed to the hun, the spiritual soul). Human + animalistic urges = …