Hug him. Say you were on strict instructions from Dumbledore to do it.
Shout da da da dum whenever he passes by or enters a room.
Look terrified and leave the hall ANYTIME he picks up his spoon at mealtimes.
Dress like him and dye your hair black. Refer to yourself as 'mini-snape'.
When he leans down to inspect your work - Grab your wand, place the tip of it directly between his eyes and shout 'Lumos!'
Ask him why he saved Harry Potter. Ask him every day.
Clap noisily when he finishes telling someone off.
Hide in his chambers at night. Wake him up by jumping up and down on his bed shouting 'Rise and Shine Professor!'
When he leans towards you in class, looming over you and generally looking menacing - reach up, tweak his nose, then twiddle your thumb between your index and forefinger and say 'Got your nose!' triumphantly.
Ask him if he knows who Alan Rickman is.
Make a habit out of grabbing Harry Potter and dragging him into Snape's office by his ears, crying 'Here he is Sir! I've got