I have always had a hard time with najasat during my period. I struggle with it each time. I live in a hot country and I sweat a lot. I feel like my private parts sweat a lot and that sweat continues all over my body and therefore when I sit on chairs and the sweat goes through I believe it’s najis. Is the sweat around the private part only najis or everywhere it spreads and usually it goes down legs and everywhere ? This makes it so hard for me.

If the sweat flows down at all, till you do not have certainty of najasat being transferred then it is paak. By certainty I mean hundred percent knowledge that najasat has transferred