Ugly Hamster: Most of those have been cited before. But again, look at body language. In just about all of them, Karen is leaning in, arching her back, and otherwise seeking closeness. Marshall, on the other hand, is almost always shown in a passive, stand-offish pose--often seeming to deliberately limit the amount of contact allowed.
Look again at the panel you noted about in
this strip. Look at the body language and their faces. He's got his eyes closed, his back straight, and his hand interceding hers--she can't snuggle up against him during the kiss, something she'd obviously like him to do. And on their faces... she's got a yearning, wanting look. Turn him on his back and you'd think he was sleeping.
The butt-grabbing scene, too, offers a bit of what I'm getting at. Note that Karen is always cast as the aggressor; not only is Marshall passive, but he drops the subject in his own mind so fast that he is smacked by his own double-entendre the next breath.
Here's a list of things we haven't seen:
His arms wrapped around her far enough to touch in the small of her back.
Marshall 'copping a feel', or otherwise initiating a simple, playful physical connection.
Marshall leaning into her body.
Marshall caressing her face or neck as they kiss.
I've been a fan of Giselle's for awhile now, since Cool Cat Studio, and Im fairly familiar with her style. If she and T. wanted us to see him being affectionate (as opposed to reading his words), we'd've seen it by now. We haven't. That suggests strongly that it's not there.
This does NOT mean he doesn't find her desireable. It means there's some other factor going on, one that's been seriously gumming up the works.
BTW, just a suspicion....
My long-running theory has been that Marshall has, in the past, been used for sexual pleasure by some girl who cared nothing about him--he was a trophy, and nothing else. This theory was further entrenched by the 'you-know-who' comment.
It is just possible that Karen's little stick-shift exercise might very well be just the break they needed. She's attempting, however clumsily, to demonstrate that this is about her wanting to know that HE is satisfied, as opposed to simply getting off herself. (It's worth noting that one of the common complaints about such half-measures is that they rarely do as much for the girl.)