To get this one you need a friend in your friend list that plays MMO Goat Simulator.
You both have to play at the SAME TIME.
If your friend have the game but is not playing it it wont work.
Both go in MMO Goat Simulator. And if you look long enough you should find a goat with your friends name above it. Lick it and you get the achievement.
I got mine by going in and out of the city of Goatwind non-stop.
After the 7th or 8th time i found a random npc goat in the city with my friend's name above it. It can take some time so be patient.