Outo no Hazure no Renkinjutsushi ~Hazure Shokugyou Datta node, Nonbiri Omise Keiei Shimasu~ - Vol. 4 Ch. 25 - A Gift For The Royal Family

[JJTheWeeb]

The rings stay ON during sex, Doctor's orders

 

[Scruffy]

It is cream puffs.
Though some might get nitpicky about the specifics (like how this one is cut open vs the poke a hole type) the basic is the same.

Cream puffs are made with Choux pastry, hence the name.

 

[Aqua_Mizue]

Thanks for the chapter

 

[Lunasol]

The rings stay ON during sex, Doctor's orders

That is correct. If it wasn't ON, then the effect went OFFLINE.

 

[Hont91]

The heck are you talking about fertility with a child that doesn't even had "the talk" yet? Thankfully the appraisal seems to be the responsible kind that doesn't share unneeded details