I would not trust this person. You can't fit an active dose of 4-AcO-DMT on a single standard size blotter (if you did they would be GIGANTIC). Maybe 1-2mg at the most, which is under the threshold; if 2 tabs actually caused someone to trip that means it's not 4-AcO-DMT. Also, he didn't give you the dosage, which is another red flag. It's probably a much more sketchy research chemical that DOES actually fit on a blotter, like 5-MeO-aMT or 25i-NBOMe. He probably either: A - doesn't know what he's doing, or B - is trying to decieve you. If I were you, I would stay far away from those tabs and get them tested ASAP. Then you could see if it's a chemical actually worth taking (if there's any at all).
As for 4-AcO-DMT itself, I've never tried it, but I've heard it's similar to mushrooms. 4-AcO-DMT is closely related to 4-HO-DMT, or psilocin, which is one of the active drugs in psychedelic shrooms. Some even describe 4-AcO-DMT as "synthetic shrooms". However, as I said, it's highly unlikely that it is actually 4-AcO-DMT, so tread carefully.