By Kayla Kibbe On-screen masturbation has come a long way since James Gandolfini reluctantly filmed an (ultimately unaired) jerk-off scene for The Sopranos. In TV’s current age of full-frontal male nudity and on-screen ass-eating, it’s not uncommon to see a character rubbing one out on your sexy streaming drama of choice. That doesn’t mean it isn’t sometimes uncomfortable — or, in some cases, downright creepy — though. You star Penn Badgley recently opened up about the challenges of filming masturbation scenes for the Netflix series, in which he plays a murderer with obsessive stalking tendenc…