Can't get your cagemate to preen you? Don't fret, just follow Beaker's simple step-by-step guide on how to get scratches!
Step one:
Annoy the living crap out of him. You need to be noticed. Announce your presence and state your desires.
http://youtu.be/2OJlNLNrPUwStep two:
Aggressively preen your mate to get your point across.
http://youtu.be/WuOwReL8vmIStep three... wait, steps one and two didn't work? Oh well. Step three: go back to annoying the crap out of him.
http://youtu.be/EkS7RbIBIZ8And there you have it! Three simple steps for mutual affection!