This has already been very well covered by all here with some great advice, I too suffered tongue bite & struggled with Va's, Vaper's, burley & the worst being auro blends when I started pipe smoking years ago, I made adjustment's to my pipes by opening the draught hole to 4mm which allowed for a more open draw so I could just take a breath to get a draw rather than a suck, also inserting the bit of the stem further into my mouth & past the front part of my tongue helped a lot, also keep the internals dry by inserting a pipe cleaner down the stem into the bowl every now & again between puffs
I now mostly smoke GH&Co brown twist's, dark plugs, strong flake & never get any tongue bite no matter how I smoke them, so for me finding the right tobacco for me played a huge part & if you are looking for a full strong smoke you will not go far wrong with brown twist
I still enjoy other tobacco's including the odd auro but I have to be very careful how I smoke them, there are seasoned pipe smokers out there that no matter how cool & slow they sip on a pipe will get tongue bite from certain tobacco's where others don't, so I would not beat yourself up about your technique or packing of the pipe too much