Basically, whenever you move your bridge, so will your tip. Stability is one of the major factors of a proper bridge. If your bridge moves during your stroke, you may or may not strike the cue ball where you intended. You might even miscue. The bridge should remain the same throughout the range of the stroke.
Comfort is another factor.
If it's not comfortable then something is wrong. The bridge should also allow free movement of the cue. Keep it loose enough that the cue slides easily back and forth. If you bridge too tight, you'll be fighting your stroke. Some players say to use only an open hand bridge, others a closed hand.