A leather thong is a sort of leather lace or rope used for tying stuff...
Also, I don't think Bruce and Dick are actually meant to be in the same bed in that pic - it's just bad colouring that makes it look that way. The fact that there are two headboards, and a straight line in the middle that's meant to be the edge of a mattress shows that it's meant to be twin beds next to each other. But because the colourist has put both mattresses as one block of white...
Two twin beds pushed together isn't any better.
Just what I was getting ready to say. It's shoddy art as the headboard and such of Dick's bed doesn't quite line-up with his mattress (but I guess it could be like one of those hotel headboards that aren't part of the bed but part of the wall) but either way Dick's bed is clearly butt-up against Bruce's bed so they're effectively "one bed." And even if they were
two separate beds not right next to one another it still
doesn't make sense because that's how married couples in old sitcoms sleep together.
It's a mansion
why doesn't Dick have his own room?!