LOL, most of the BP yawns I've seen are just really darn cute! I don't know what possessed Rae to go for the "GRAWR!" variant that day.
Gintama is a wonderful show! Admittedly the number of episodes is daunting, and I haven't watched the series in its entirety either (I want to guesstimate that I left off around episode 170-ish?), but it's given me a lot of laughs that I still reference as running jokes with the friends who watched the series with me. And for such a wacky and comedic show, it also surprises by really delivering on the production quality during the major story arcs where it takes itself seriously.