looking for a fic where the horn is used as a cock and includes magi-cum

https://www.fimfiction.net/story/2060/twos-company-threes-a-crowd

It's SFW but it's the only one that I know

6999253
Off the top of my head I can think of this one:
https://fimfetch.net/story/121703/not-so-banned-from-equestria

https://www.fimfiction.net/story/166496/fecundity
It happens twice in this.

thank you i'll look them up^^

6999264
what chapter if you remember

6999263
its on fimfetch? do you remember what chamber has the horn fucking

6999672
All I remember is that it involved Princess Luna. And yeah, the author pulled all of his stories from fimfiction some time ago, so it's only on fimfetch now.

6999671
My mistake it only happens once in chapter 18.1 towards the end.

There's also Mr. Twilight Sparkle, where Twi does it to Pinkie Pie, but they don't realize that Pinkie got knocked up right away, or even know that was possible.