I find that most tobaccos that I need to rub out (flakes or roll cake slices) have a fairly sharp bite if I don't let them dry out for about an hour after rubbing them out as futureman mentioned. And also like futureman, I get the bite worse with sweeter blends.
Last week I got some Mac Baren's Dark Twist, which touts itself as being sweet. Most people rave about it, but the first few times I smoked it, my tongue and the back of my throat had a really sharp bite going on. I realized that it probably had something to do with the tobacco still being compressed in slices of roll cake, so I rubbed some out and let it dry for about an hour. Turns out that when it's dried out enough, it's as fantastic as everyone says it is, with no bite.