It's time to suggest a NEW tag:
"Young Master Fucks the Maid"
or (to put it more gently):
"Young Master Loves the Maid"
For the best (and funniest) example of this trope,
see Ishikawa Shisuke's Young Master's Struggle,
which is written in the cheeky style of a Victorian
porn novel. I also recommend the saucy prequel, My Master Is a Naughty Brat.
A Nigh-Irresistible Combo to be found in Ai-san: Osananajimi x Maid x Sexy Onee-san (I'm guessing she's the slightly older of the pair). Tadaatsu could find no better Waifu Candidate in his life. And props to Otou-san ("Dad") for engaging "Wing-Dad" strategy ... it was Super-Effective!
In The End, There Can Be Only One conclusion regarding this work ..... "APPROVED!"