I had stuff laced with crack and it tastes kind of like its carbonated. as if you were tasting soda.

but just get someone u can trust cuz ive smoked a lot in my life and only had laced stuff once, and the guy who sold it to me told me that it was "funky shit" so i should have known anyway. Most people wouldnt lace yor weed anyway unless they were trying to be nice or trying to get you back for something..