I find stoving helps with tongue bite, as it drives out ammonia. But in general, extremes of tobacco humidity, as well as rate of puffing, are the primary culprits. A properly packed pipe is less likely to bite, as it burns slower, along with tamping. And then pipe architecture is a consideration, too--if the stem hole is aimed right at the tongue. One can try dangling the pipe a bit to aim the smoke between the tongue and palate and not directly at either. For that reason, I suggest starters go with a bent shape for their first pipe. They're also less likely to get a mouthful of condensate, too, as it tends to follow gravity back towards the bowl.
Pipe smoking is such a symphony of subtleties, is it not?