Among the many times I had the good fortune of serving Thrangu R., one was cooking for him at a mahamudra retreat in Maine in 1999.
Rinpoche and his translator, Peter Roberts, strolled through the kitchen while I was making a Himalayan-style lamb stew for the very first time.
In a playful mood, I said to him, "Rinpoche, you are my guinea pig."
He smiled and nodded. "Guinea pig," he repeated, then walked out of the kitchen.
When I later asked Peter about that interaction, he said, in his wry Austin Powers accent: "Rinpoche couldn't understand why you were comparing him with a rodent."