Yes a real problem "Hot Nuts"
But seriously if it is caused by heat,
Wear something like LD comfort riding pants to wick moisture away from the skin, use a bead seat to increase air flow under your butt and try using an air deflector on each side to direct airflow into your groin area - Modified Baker Air Wings as an example.
If the burn is caused by saddle time, then try altering your seated position occasionally, try standing up and doing some squats and change your leg positions, this takes the pressure off and allows some circulation into the area.
For the record I have had the Numb Bum and the Hot Nuts too, finding the right combination is an individual thing.
I have tried -
The stock seat by itself, with an air hawk and with a bead rider,
I changed to a Corbin because I did not like the seat sliding me into the tank, with the Corbin I have done LD on the bare seat, with an Air Hawk and with a Bead Rider.
The Corbin is as hard as concrete as well but you do get used to it.
I use the LD Comfort Shorts and I have settled on the Bead Rider, Simply for the improved air flow, it also lets the water drain out while riding in heavy rain as well.
This works for me, I still find on long days that I will stand in the pegs now and then, I also have Hwy Pegs to stretch my legs out as well.
Best of luck with finding your own solution, keep trying
Cheers
Paul