Preventing the heavy bag from swinging

1 Clinch punches, standing against the bag and holding the bag with the other arm and doing punches.
2 Holding the bag with one hand and doing hook punches with the other hand.
3 Double hook punches.

4 With a heavy duty, thick bar rack it's possible to hold the rack with one hand and then hit the
  heavy bag with the other hand.

I also do this in my house and it works very well.