Although I didn't draw it, to me it looks like 2D, Noodle and Murdoc are playing some kind of game while in fancy dress, and Russel's just entered the household thinking "I walked in at he wrong time... O.O" XD link ^ によって the original artist iricolor.
2-D and Russel are just being 2-D and Russel (Russel in his エモ corner while 2-D tries to re-enact his idol, Murdoc) Murdoc is drunk または being playful with the newly adult Noodle, who is probably 'experimenting'. With something...I dunno... Either alcohol または being sexy...It's not like she has much options, being stranded on Plastic Beach!
