Since a young teenager a have had a fetish by masturbating using Down Jackets (With Nylon Material). Also known as puffa Jackets.
I get arosed and fully erect with just the touch of the sexy silky material against my penis.
My best position is to turn the sleeves insideout and zip up the jacket with it back to front around the waist with the sleeves dangling inside then put my hands though the outside sleeve holes and wrap the material around with a hand loose around my penis and then use the usual stroking. (wanking movement) I try not to let the cum go on the jacket as my Family doesn't know.