For this steal, 2 jugglers are passing 4-count (you can generalise it after). A third juggler is going to come in the middle of the pattern. The idea is to steal a pass going from one juggler to the other and to replace it with another club. The animations below may give you an idea of the position of the clubs and of what is happening during the movement.
The blue juggler will take with his left hand a pass going from the red juggler
to the green one. In the same movement, they will put the club they have in
their right hand in the hand of the green juggler. The arms are crossed during
this movement, the right arm goes above coming from the top.
The club has to be caught by its body (left hand), at the moment where the red juggler has just thrown it, so that the handle may be placed in the green jugglers hand.
When juggling a 4-count, the movement can be done every pass with a handacross from one hand to another between every pass.
To complicate further, the blue juggler can "replace in passing" (from the red juggler to the green one), and then replace (on the right hand of the green juggler), then turn 180° and do the same, continually changing direction. Both the green and the red jugglers have to be familiar with the 2 kinds of takeout to manage this pattern, whilst the blue juggler alternates.
Another idea is to add someone else who plays the same role as the blue juggler, replacing just the passes coming from the green juggler to the red one.