It's only a "sin" if you don't enjoy it and don't get a fabulous release!
Christian leaders and philosophers have gone way out of their way to spoil an individual's sexual life for many millennia. The big lie is that there is a separation between a person's body and a person's mind---dualism---and that living in one's head and puishing the body is a good thing--IT IS NOT A GOOD THING! In reality, an individual **IS HIS/HER BODY** which includes a brain, hence consciousness. The body is *not* to be punished deprived or scorned, WHAT NONSENSE.
Individuals are their bodies! Just to reiterate. It is unhealthy to think with Dark Ages (my definition-fall of Rome to the Enlightenment) speculation done by weird guys who had no knowledge and plenty of neurosis'.
I'm a follower of Aristotle.....**EVERYTHING** in moderation. (Including "religion")
Have a full well balanced life, everything in moderation.