[RevSmoke]

1) How loose is it? If it isn't "falling off" loose, simply smoking a bowl in it will correct the issue as the pipe heats up and moisture gets into the stem.

2) If that doesn't work, take a simple candle and rub it up and down the outside of the tenon. This should tighten it up so that it is no longer loose.

Never, I repeat, never, use the technique which will cause you to change the shape of your tenon. Why? It fit when you bought it, it will fit when the temperature and humidity rises. If you change the shape of the tenon, you will have issues later.