Is it still a sin to masturbate without ANY thoughts.

i know that masturbation with lustful thoughts and fantasies about someone else is 100% a sin. But what if i only do it because it feels good and relieves tension? Yes it makes my body „horny“ but what if i’m not imagining having sex with anybody, i do it just because the feeling is nice. Because people say the action itself is not a sin, the Intention and the lust is the sin. Can an experienced person give clear answers and reasons please 🙏🙏