Desk Humping

I have parents, susters and brother who don't knock before they enter, so when I masturbate I usually put on a skirt with no panties (that way if they interrupt they can't tell). Then I open my lips and place my clit on the corner of my desk. I take my feet off the floor and place my hands on the other side of the desk. I pull myself up and slide back. Every now and then I squeeze my legs together until I get an orgasm.