Is a man wearing a thong normal?

Yes it is

==== doesnt matter if you're a guy or girl.. wearing a thong / gstring is perfectly normal. its what ever makes you feel more comfortable Yes, I wear one and it feels real comfortable

Why worry what others think, go for what you comfortable with. If we only wear the cloths that others think we should ware, our wardrobe would be very limited. Contrary to popular belief, there are no fashion police.