Again - thanks so much for sharing the links. I skimmed the episodes and have a nudity summary to save you time. As always Maria Bopp performs the nudity. Not as great as previous seasons for nudity but still solid. Sex scene is episode 1 and 3 are the best.
S04E01
33:28 - in a great outfit wrapped as a present, begins a fully nude sex scene where she shows breasts and ass, gets nipples sucked, best shot is at 35:23 where you can basically see her shaved pubic mound which is only partially covered by her hand when she rides a guy. in HD you can almost make out how her fingers move her lips
S04E02
9:56 brief glimpse of full frontal when she is getting fucked from behind
42:13 brief topless as she slips out of a fancy dress
S04E03
8:00 topless as she sings and dances in front of a mirror
14:15 fully nude sensual sex scene, you see her topless, with nipples sucked, deep french kissing
21:48 she is nude and double teamed by two guys, ass and tits visible, maybe a glimpse of shadowy full frontal (WARNING: the two guys are playing with each other and making out as well)
32:30 a different actress recording herself on a webcam. hard nipples in a thin shirt, then a topless covering with her hands. I think she's playing an underage character.
S04E04
2:44 Opens on a party with a couple of hot topless women (extras). Nothing else noteworthy
S04E05
39:47 blindfold, she's naked but you see her topless, she licks all over the stomach and chest of some guy, then licks a candy (?) rubs it on her nipple before rubbing it into her crotch/ass. one guy enters her from behind while she makes out and goes down on a second guy all while a third guy is in the room. they take off the blindfold to reveal that she is being fucked in front a group of women (who want to be prostitutes?) and she is upset to see that the young girl she knows is in the group.
S04E06
2:09 continuation of the ending scene from the last episode. She freaks out and one of the guys she was fucking restrains and chokes her and as they are struggling you see her topless and a quick glimpse of her shaved mound. He chokes her until she is unconscious.
Nothing else
S04E07
Nothing
S04E08
Nothing