We Went Swimming

Its not much of a story I went swimming with my friend we changed after our swim I was drying off watching two girls exercising bending over etc. there costumes were slipping up there cracks I could see pubic hair I got a good erection my friend grabbed my while I was watching and wanked me off, I let him because it felt so good, I felt ashamed after but wanted it again, I am a bit confused about it