Well, here's my two cents worth.
I am going with the assumption that the OP is not talking about Chinese people in general (i.e., he's not talking about huaqiao, or the Chinese diaspora) he's talking about Chinese students in Mainland China. Like every other country in the world, China has its own customs and ways of doing things--I don't mean eating with chopsticks, I mean those little everyday differences that you'll never find in a guide to cultural differences.
I've lived in Chinese dorms. I had a Chinese boyfriend for six years. So what I'm about to say comes from my personal experience. It will not apply to every man in China, naturally. But it did apply to most of the men I knew there.
Teenage years are often very difficult in China. There is lots of pressure to do well in school and to pass exams at a high enough level to get into better schools. The day begins early and when school lets out many of the students go to cram schools until eight or nine in the evening. After they return home, they do their homework. Its a never ending cycle. Although I knew many guys who masturbated for the first time during their high school years, I also knew a not-so-small number of men who never jerked off until college. Part of this is because their days had no free time, another reason is there was precious little privacy in their homes. I didn't believe them when they first told me, but after living there for several years I can now see how some are late starters.
So, yes. Chinese guys do jerk off despite what one person in this thread said. The next thing to consider, is that China is mostly a conservative country. Cities such as Shanghai might lead you to think otherwise, but that's misleading. So, you're not going to find Chinese guys talking about jacking off. Just imagine all your fellow students are from very small towns in the Bible belt of America. You can be they're doing it, but they're not going to advertise the fact. They're going to be as private as possible about it.
If you go to the Answer section of Chinese Yahoo or Baidu, you'll see lots of guys posting questions asking if masturbation is harmful. Some of the answers may surprise you. Some posters--and also some government websites--say it is harmful. They quote the old folk believe that one drop of semen is equivalent to ten drops of blood 一精顶十血. Even my dictionary 现代汉语词典 published a few years ago adds a warning to its definition of masturbation and says that it is harmful to your health. These opinions are dying out, but they still persist. So, some people will view masturbation as a bad habit.
Just last year in Dalian a middle-aged man and I were talking. He was worried about me because I wasn't yet married. He then proceeded to ask me about my opinions of Chinese prostitutes. I told him I didn't know. He was shocked. He said that if I'm not married then I must be visiting prostitutes otherwise it would be very unhealthy not to have sexual release. I mentioned that I jerked off. He was aghast. He thought that was more injurious than not having sex at all. (He may also have been aghast because I said it so directly).
So, in short: keep in mind that the country is largely conservative when it comes to sexual matters and that old myths about masturbation still abound--although even newspapers now are printing stories discrediting these myths. Your Chinese classmates are doing it, they're just not obvious about it. You could try asking some close classmates to teach you slang and then work the conversation around to the words for jack-off. I would be discreet in choosing who to ask, I've alienated classmates before by being too willing to discuss sex. (Again, its not that they don't do it, its that they don't think it should be talked about).
The above has been my experience gleaned from six years living in China and numerous visits back. I hope it helps. And, as China is changing every day you may find things different from what I've described.
