How to get comfortable sparring with close friends and training partners?

i train in boxing. im 15, 5'7'' and im pretty good. i fight like a boxer ; not too aggressive, use my jab a lot, and don't go bull rushing in with lots of punches. i have a good friend who trains at the same gym i do and our trainer works with us a lot. he usually partners us up along with a few other close training partners of mine. anyways, we do a lot together. we help each other with heavy bag work, and give each other tips, just things that good training partners do. however, i find i am uncomfortable when sparring with these people and i think the reason that is is because i know them and i am close with them. in sparring sessions, i find myself pulling my punches and not really following through. i hit them during sparring sessions as if i was a child with no punching power. i pack a punch though, and if i really committed my punch would do some damage. like i said though, i know these people and i am close with them. ive spoken to them about it and they tell me not to worry about it and we are just helping each other out. despite this, i still feel uncomfortable sparring them because im close with them. how can i get over this and stop pulling my punches when i throw them. throughout the whole sparring session i am just jabbing, and straddling around them. im just moving around and i barely ever shoot the right hand, and if i do, its like a love tap. luckily for me, my defense is good so i can just work on that but i would like to be able to get more comfortable and stop pulling my punches. any tips? thanks guys!