actually in yaoi is the obly place you can find nipples, in shonen is were you cant or in shojo ddkktt
There is this unwritten rule where the semes don't have to have/show their nipples specially if the seme is irresistible ukes Have to have nipples. Though there are some cases were both have/doesnt have nipples, seme has nipples and uke doesn't and vice versa XD
The last page tho.. Such confident uke isn't he? Haha
But damn that body! ლ(´ڡ`ლ)