I can't restrain my self from sucking cocks.why?

(INDIAN)
At first i haven't given any thought about cock sucking , but when i was in my +2 i got a bit attracted to my friend and tried giving him head in the night although he didn't let me , so it didn't happened in my +2, but he reveled it to my whole college.
But when i joined my B.tech everyone in my college came to know about this matter in my +2 about me (word goes around right), and so people kept me away for being ... what ever i am ,as the time goes on i mad one friend who i thought was mature among the rest of the guys, (ya even girls kept me away) but later at the end of my B.tech i figured out what is he up to that is in 3rd year , he's been expecting me to suck his cock daily at nights, yes i know i should not do it but some how i forgave him and sucked his rod, after that he's changed completely he only talks to me when he is expecting it from or when he need my help in any other matters, its like he is treating me like a sex object.Eventually getting his rod sucked has became a common thing and began to avoid me from doing it, now he only lets me when his GF excites him too much or when he is very horny.