MASTURBATION

Ali
What's your opinion on masturbating. 
I masturbate sometimes but because I'm a Christian I feel like I've done something wrong when I finish. Does anyone else share the same feelings. 
Also is it okay to watch videos of other people masturbating. Once again I always feel bad about doing stuff like that. I feel like I've committed a sin. 
I'm 13 if anyone is wondering. 
Is there a way for me to feel less guilty.