He could be slutty as hell (very literally Pansexual), or maybe he thinks that sleeping (in case of Chitauri/Jotunheim) will get him what he wants, or maybe he thinks it's a way of getting him allies (Loki/Villians maybe)... but he makes those decisions of his own violation (no consent issues).
Threesomes and Gangbangs are also fine as long Loki is getting banged and it's all completely consensual. No Loki/Avenger end game though (except Hulk/Loki, I ship Hulk/Loki).
P.S. Could you warn for Hard Kinks (BDSM, bathroom-play, pain-play) if it's not already?