I agree with Playful the touchy feely type. Actually not only that, the playful fun touchy feely type to be precised. A lot of people just tickle people for fun.
My first ever true gf had a best friend who was always tickling her and in fact told me to tickle my girlfriend. I still remember on msn messenger
Me: How do you know she is ticklish? P: Well because I tickle her lol.
But she was definately the touchy feely type and always tickling my gf's sides.
The most memorable time was when I was on the phone with my gf and she wouldn't stop giggling.
I also recall back in secondary school some of the boys who would keep touching the girls would usually end up tickling them at somepoint.
My ex fiancee's nephew also came to visit her a few years ago, I noticed when I first met him he was a bit of a touchy feely type too.
Not to my surprise as soon as he discovered she was ticklish he would keep tickle attacking my fiancee..