Got the chance to roll with two distinct black belts : a renzo gracie bb and a marcus soares bb. Got amazed at the level of control, but retrospectively thinking, they were sometimes slacking down on me, other times going 100%. Resisted close to a minute with each one, holding my position, or sweeping.
Learned and saw a very nice kimura, armbar sequence from mount. Attack one arm with a kimura, and as the person pushes with the other arm to make space, arm-bar it.
Almost got choked out : didn't feel this new gi choking me, until I started getting dizzy.