Okay, after reading here is my short story. Myself, 13 yo son, from early in life short marriage, went camping/dirtbiking in the mountains using my tent. My GF went also, as she enjoyed tenting too. She was just 9 years older than my son.
Well it gets cold at night, in the mts. I always put the lantern in the tent before bed time, to warm it up. You know what is coming, GF goes in tent to get ready for bed, while son and I put fire out. Yep, you are right, we could see right through that tent. First came pants, then shirt, undergarment, WOW! Son looked at me, I looked at him, all we could do was start laughing. GF says; you guys can see through the tent, right? I said, yes honey, and you look fabulous!
That had to be one of the sexiest silhouettes I have ever seen. She did not need the "fitness program". I ended up marrying that girl a few years later. She and my son are still friends too.
Jerry