The safest thing is to massage yourself. Through scientific and systematic massage training, it will naturally become bigger. I am an example myself. I didn't understand before, and I bought thousands of pieces of ointment, and the effect was minimal. There are so many hormones that I dare not use them.
Later, I studied with Nutu's VIP technology and massage methods for two months. It's 36C now, and it costs nothing. You can go and have a look. That's awesome.