
Read this to understand about Alpha knotting. (Similar to canines and felines):
http://www.mangago.zone/read-manga/abarenbo_honey/nbt/6d5913acc7b0dbb2/ChChapter_1/6/

Its when a penis(canine) reaches the climax and the base (the tip here for some reason) expands or inflate like a hard bulb forming a knot that prevents the penis from pulling out so that the semen doesn’t pour out and ensure better impregnation. It usually takes about 30-40mins or even an hour for the knot to go down. Hope this helps
wh?? so what does it mean if they knotted?? and why do they have to wait until morning?? #-.-)