Can also be used in other tenses and variations like:
I'm going to dial in that letter to my landlord before I send it out.
That bike needs to be dialed in before we take it to the track.
I was dialing it in yesterday so that it would be ready for the trip.
2) I went out with this chick, she came back to my place and I dialed it in.
3) Person A: Hey, Wanna go to the bar?
Person B: DIAL IT IN!!
Origins traced back to eletric guitarist slang... referring to fixing of the guitars for someone... be it through tweaking the dials or turning the knobs that tighten the strings.