I think that was intentional. Not only as a nod to Ash's self control but also to show the readers what exactly he's been referring to whenever he tells Lyle how much he's holding back.
Yeah I'm sure this is going to progress into spilling all the feelings. And I know Ash didn't see it as sexual assault, or at least doesn't blame him. I just think it was unnecessary and it was already at the breaking point that I don't think a rut was needed. At least wasn't needed to the extreme it took.
Not even that. I think readers have this idea of Ash and this is the author's way of saying there's a lot more to him than meets the idea. So very necessary in that sense. (Imo anyway).
Okay yes the dude was in heat, but his entire personality with his self control left. But did the author have to drag it on for so long and make it look very much like rape. Could have been less focus on the forcefulness.