Usually the visitor if their is one calls it.
You have to be specific about your called posture or else the opponent can get in and out however they can.
You may combine up to two postures any more doesn't count and could result in losing a turn.
You may not repeat the same posture more than once, however you may use that posture in a variation or combo with another pose.
1.....2.....3......GOOD and held up to 30 sec max.
If a player is in a balancing strength posture and taps the floor to get their balance it is ok up to 2 taps. Then the posture does not count.
Player can call up to 1 second attempt each.
When you are down and out Y-O-G-? you get a second attempt before facing the pit of misery!...kidding, but you do get 2 try's.
Good Luck and Skill!