I've started to be more open about masturbation with myself recently, and have been exploring different ways and techniques (and have been planning to buy my first dildo!) for a little while now.
This technique I use often when I feel horny during school, and feel like teasing myself. I will purposely sit next to the guy I like, or some hot guy, and create a sex story as I write it down on scratch paper or whatever. Not legible handwriting though. I'll write the words layer over layer, in sloppy handwriting so it just looks like a bunch of doodles. It's incredibly naughty feeling and exciting to write about having sex or other sexual activities while sitting right next to the person you're writing about, and if it all becomes too much I'll excuse myself to the bathroom to jill off, or usually just replay my fantasy in my mind as I masturbate at home.
Everyone should try this sometime! If you enjoy writing it also may inspire some good sexy fiction to submit.