Reduce the gas on your flame to decrease the width to about 1/2 of the width of the involved glass. While rotating, heat the glass and lightly feed the glass into the heated region. Notice that the glass in the heated region is thicker than the original wall thickness. If it appears that the inside may close up, quickly blow into the glass to increase the diameter of the working area to continue working till all the folds are uniformly melted. Also, be sure to not bounce the glass in and out of the flame as you rotate. Not maintaining the glass in the flame will prevent the glass from getting sufficiently hot enough to properly melt the folds caused by step (3). The longer you take during this stage, the more glass you get involved in the seal, the more difficult it is to control the glass and the less good the seal will end up looking. So, you must heat the glass very hot, quickly, with a narrow flame. Always, slow rotation is better than quick rotation of the tubing.