Geralt would prefer to stand-- in fact, he'd prefer to stand with his sword at his side in front of the door, ready to cut down any man who'd try to enter. This would do nothing to help the reputations of witchers, of course, nor would it be particularly subtle for him to skulk around the door like a surly guard dog, but his desires don't always line up perfectly with what is prudent. And what Jaskier is asking of him is a small thing-- just so sit with him, like friends. To talk like they used to, or, maybe, not how they used to, since Geralt would rarely talk.
Better than they used to.

The witcher sits on the edge of the bed, but only after moving his swords so that they lean against the wall in easy reach.

"You've been back to Cintra."

It's not a question; Jaskier knows the princess' name and what she looks like. He must have seen her at some point to know how much like her mother she is, and, really, it's unreasonable for him to assume that Jaskier would stay away from a well-paying job just because he wanted to give Cintra a wide berth. There were times that they had separated. Jaskier just had the foresight to plan his trips to Calanthe's court at times when Geralt would not be with him.

"Ciri is more like her mother than you'd think," he says. "She has her gifts, too. It's why Nilfgaard wants her so badly."