I really wanna gain some weight because my friends make fun of me that I'm really sexy I currently weight 72 kg and I wanna gain 10 more how do I do that doctors???

Culture? I know very little abut your culture but your weight is good in consideration of the US culture. This weight is average for a male of about 68 inches or so. The way to gain weight is eat more and less activity. The intake and expenditure of weight is the key. Bananas will help as well as high caloric foods. Not sure you need to.