There is an anger that comes from seeing one of your mates heartbroken. You have to tread carefully (ha, see what we did there?) around their emotions which can pinball between anger, denial, wanting to work things out etc. Just let them know you've got their back with this pouch that wishes an acceptable amount of pain on the ex.
 
FYI, this doesn't have to be limited to breakups. There are many instances we can think of when willing someone to step on Lego is appropriate.