This trophy is not complicated, but still a bit tricky. To do this, you need to unlock the Headstomp move first, which is pressing
while in the air. For this trophy, you will need to stack up 10 consecutive hits without getting hit yourself or touching the ground.
A good location to get this done is the fight against Gideon in the level 7 "Subspace Highway?" sub-stage.
After you got rid of the heads, start the attack and then repeatedly keep pressing
. The timing when to initiate the attack is the key here.
See the video by YT user Pat Glet for reference.