D2: Tool for retracting brake pistons?

[notorious]

Hello all,

I'm going to change my front and rear brake pads soon.
Doing this myself for the first time.

I understand the trickiest bit is to retract pistons.
Should I purchase any specific tool, like a clamp, to retract pistons 'properly'?

Any advise will be appreciated.

P.S. My car is normal FL A8 with floating front callipers. Non-S8 version it if helps.