witchers have a fantastic senses. they can hear when your heart changes speed, when your breathing shifts, and possibly a whole slew of other things from the humans around them.
what if j/ask has the kink, has always had it but never mentioned or indulged. and G/eralt has known the whole time- from the clues, but didn’t know how to use this information or breach the subject.
Even later, when they’ve allowed themselves to tentatively love on one another, the w/itcher is at a loss on how to ask the bard about it.
Perhaps G/eralt navigates them through an area he knows always fucks with his sinuses due to overwhelming and colliding scents or he feels a bad cold trying to take hold and er... encourages it if only to give him an opportunity to ask/indulge his bard.