When I was in high school, I worked up the courage to privately compliment some of my female classmates on their long hair. If you're particularly polite and respectful about it, some of them may let you touch and or even play with it.

One classmate had very thick and even light brown hair down to her hips, and I was observant enough to listen in on a conversation where she was telling one of her friends how she loved having someone to play with her hair. I found an opening one day when we were alone in the study room, and I persuaded her to let me take it down, brush it out and braid it for her - I even secretly rubbed it against my thigh without her knowing. She apparently enjoyed me playing with her hair so much that she met up with me at least once in our university years to relive our hair play sessions for old time's sake, before she eventually cut it into a bob for work reasons. (I actually met her again last month, and she's been trying to grow it out again from shoulder length)

Another classmate had dirty blonde armpit length wavy hair, and while her friends were distracted, she let me put her hair into a braid. Apparently, I also did a good job of it, because she ended up keeping that braid for the rest of the day, and actually quietly (and apologetically) asked for my permission to undo her hair again when school was out.

A third classmate had straight caramel brown hair down to her armpits as well. We were walking home together from school one day when I pretended there was a leaf in her hair, and used that as an excuse to start playing with her hair as well. She ended up talking to me for a while about her favorite hairstyles (braids and french braids), and thanked me for taking the time to help get the knots out of her hair. Unfortunately, less than a week later she cut it to above shoulder length.