cbiggs11 said:

It's probably referencing shipping between Silver Spoon and the CMC, Diamond Tiara, etc.

Possible, but there's no physical indication that says the dick belongs to a female. The only things we can see are the young gal about to get penetrated by an unspecified lover.

But if this image was an epilogue to a comic that says otherwise, then maybe, just maybe the tag might be justified.