Is it haram to touch my nipple( I am a male teenager ) and slightly stimulate myself?

When I stay alone like the time of studying I automatically have thoughts like having sex with someone, these moments are very disturbing for me , I can't do any work then .( I am a male teenager).. If I just touch my nipples then I feel slightly excited, and I feel better then , but I don't touch my penis , so I don't musterbate...so is it okay to touch my nipple and slightly stimulate myself ? I don't think about sex ,just touch my nipples and it slightly stimulates me . That's it .