It is said/used after successfully tricking another person. Sometimes used to tell someone you were being sarcastic about the matter.
If used correctly, the other person should say "arms" or feel the emotion behind "arms".
James:" Hey, do you think I'm so pro in LoL?"
Jesse: "Of course, who's better then you? :3"
James: "I kno right?
Jesse: "Trollie face"
James: "ARMSSSS"
When I man pulls out before firing to avoid making the female pregnant (trolly meaning pushchair/pram)
Tom was enjoying penetrating Emma and at climax pulled out and ejaculated all over her breasts, only as he realised his mother would kill him. trolly dodger