In the Smash Bros. series, Peach performs the attack by hitting her opponent with her rear. Upon impact, there is an explosion of hearts (an explosion of fire in Melee).
In Super Mario Dream, Peach performs the attack very similarly to how she does in the Smash Bros. series. Sometimes, however, she may not use her rear to attack. In some episodes, Peach may perform Peach Bomber by simply tackling her opponent while facing forward instead of using her rear.
In Mario Tennis: Heroes Vs Villains, Peach uses the move as her Trick Shot to get to one side quicker. By presi g the right stick left or right she will perform this move and it may slow down time for a short period of time too if timed too late or too early