Welp since I re read this again. They do, but they don't show it. And they do it because of the uke being magic sick since his from a parallel world where there's no magic and more over he accidentally entered the world during the summoning of the saintes(he wasn't invited) which gave him no protection against such of the world unlike the saintess.
Why did they do it?:
The uke sleeps with the seme so that he can get used to the magic and everything.(The seme slowly and uses magic bits by bits into the uke's body)You'll understand this in chapter-6 where the uke was overdosed with magic potion.
there’s no smut but as someone who usually avoids shounen-ai for that reason (yes I’m a deviant) this is 100% worth reading just for the plot in my opinion
Do they fuck, like genuine question, do they do the deed and do they do it good.