Responses
Yaoi's uke aren't normal human beings, they follow the rules of yaoi world : elastic anus and total lost of strenght when turned on
Don't forget self lubricating and able to have multiple orgasms.
This author seems to have a ton of couples where the poor virgin uke just gets it shoved in with no prep or lube. At least the dog was nice enough to try and stretch out his partner, the humans just shove it on in. Maybe they are just hoping for blood to act as enough lube, although there never seems to be pain involved.