Make a list of your favorite pairings and explain who would pick up the socks and why.
John/Zep: Zep would, of course! He lives to serve John.
John/Amanda/Zep: See above. Dear little orderly Zep adores both his lovers enough to be laundry servant to the two of them.
Lucius/Walden: What do you think house elves are for? :P
Ben/Locke: I have a feeling Ben is sniffy and fetishistic enough to wash all the socks!!!
Pamela/Jason: Pamela would pick up the socks, like the good mommy she is. But she'd probably yell at Jason for getting blood all over them! Bless.
Freddy/Jason: Socks don't exist in your dreams! :D
Gabrielle/Luna: Socks would be cleaned magically, naturally! Though I have a feeling Gabi would prefer to wear stockings unless she's in a Sweet Lolita mood.
Batman/Joker: Bruce probably has a laundry service.
Cthulhu/Idh-yaa (the "quasi-female" and "androgynous" mate of Cthulhu according to Lin Carter): Great Old Ones don't wear socks. Otherwise, I've a feeling that Idh-yaa would try to eat everything in sight (including socks), or want to train shoggoths to do laundry. ;)
Silas/Aringarosa: Silas would, of course. Part of his beloved corporal mortification! ;)