Hamill's lightsabre

So, maybe I watch films a little too intently but..... there's a scene in the Eye segment where Luke Skywalker is on top of Twiggy. We see Luke's naked ass but it actually looks like he's really in there! No flesh pants. Nothing! I guess my point is, this scene carries more realism than the infamous one in 'Don't Look Now'! Are Luke and Twiggy method acting?