In the first episode, we see Ai breastfeeding one of her kids(Side of breast is shown)

A character calls another character a Lolicon( A person with a desire for young children). This is because it was implied he liked 2 16 year old girls.

A character claims that it is weird to be breastfed because they are reborn as babies. The other character claims that she will still suck her mother's breast as shes a child.

A baby says "bitch" in one scene

Occasional use of Sh*t

In the first episode we see some characters smoking but that's about it

The Character the director smokes in a few scences throughout.

Oshi no Ko at first seems like a light hearted anime, however as the episode goes on it gets progressively darker and more depressing.