I started masturbating when I was a lot younger. I remember rubbing myself with a washcloth in the bath and it feeling good, and humping my duvet in bed before I fell asleep. Around 13 I started to use my fingers more, slipping a hand into my knickers whenever I was horny, sometimes three or four times a day.
Around that time I discovered a penchant for wetting my knickers. I hated the school toilets, they were disgusting, but one day I was so desperate for a wee that I knew I was never going to hold until home time. Between my last two classes I slipped out of a fire door into a courtyard that was never used. By this point I was leaking into my knickers anyway, and so feeling incredibly naughty I parted my legs and let go, a torrent of pee splattering onto the concrete and over my shoes. I quickly wiped my shoes down and went back inside. I could feel the soaking wet cotton of my knickers pressed against my pussy under my school skirt, and over the course of my last lesson I became more and more aroused.
This was where it started. A few days later on my walk home I decided to do it again. I often cut through a wooded area on my way home, so I strayed off the path slightly and parted my legs, soaking the leaves underneath me. I was so horny I almost ran home. I lay on my back on my bed and put my hand down my wet knickers. I'd cum within a minute.
This has become an almost daily routine for me now.