Hiiiii! This is a cute little doggy cock you've got there. Don't try to force the knot in while playing with it, always make sure to stretch really good before attempting knotting. I recommend using a big plug or your hand (however much you can fit in :3) to prepare. And, of course, remember to wear thigh highs!
I have got a boyo from YOCY (bought on amazon). I can easily take the shaft but that knot is SOOOOOOOO big, I can only take the very tip of that bulge. Trying to stretch my butt with my hand, might post a video once I get that cock in :3