The Drake and possession spirit, A GM's headache, and magical boxers. Options

[Alexander Ni...]

Alright, I'm sure the topic of drakes and shifters reverting to bestial form while wearing clothes has come up before but this happened to me last game and after nearly two weeks of quietly weeping I still haven't figured out what to do with it. I hereby ask you great sages of Shadowrun for help.

"Bob" the drake (not his real name) was put into a police car to answer a few questions, Bob is a SINner and though he is a Shadowrunner he isn't very good at it. One of my "thinking outside the box" regulars decided that he would summon a rating 9 Guardian spirit but I informed him that due to his tradition he needed it to possess something to affect the material world. He chose the drake's underwear....

Logic was there (they won't strip those off will they?) and I allowed this. Later during the game, in a scene the police car is attacked by my 'mysterious villain' and my drake player goes "Full Drake."

Now I'm stuck with, what happens when a Drake tries to expand inside of human sized underwear that happens to be inhabited by a force 9 spirit.

Thank you in advance for your feedback.