[Xfx7028]

I also do this.

I lived most of my life in the Mediterranean country and lived in a apartment on the top floor with just a concrete roof where the room temperature was 34°C even at night.

The solution I found was to take frequent cold showers. Stay under the shower for some time, like 5-10 mins, until you get cold, and then without drying yourself, lie in bed naked. I also felt so cool that I even put a blanket over me. It takes a while until you get warm again, so it's enough time to fall asleep.

For more extreme hot situations you can put a wet cloth/t-shirt on your body, but I think that might be unhealthy.