We have been working on perfecting ganchos ("hooks") and leg wraps in my advanced class this session, so I wanted to underline what technique needs to be in place for the follower to have a loose leg and good axis; and the leader to have the timing of the step perfected.
Followers: the secret to a good gancho is a good back step
The best gancho comes from making the best back step that you can do. When I see people preparing for ganchos, what I often see is abandonment of solid, basic technique. We get excited about doing a "fancy" move, and forget we know how to walk.
Also, when a gancho comes from an overturned back ocho, the angle of the pivot that prepares for the step is very important. The leader does pick the angle, but when I feel the extreme twist the leader provides, as a follower, I give my best, on-balance pivot. I try to pivot so that my butt is almost facing the leader.
Keep your legs collected during the pivot to get maximum rotation. Make sure that you are not sneaking the free foot out to get started on the back step of the gancho: that slows down your pivot and prevents you from getting the most you can out of your preparation. If you are even an inch or two further away from the leader, a gancho won't work.
For your back step, feet, knees and hips are in flexion and soft. As soon as you roll through your heel, the free leg needs to be elastic all the way to the hip. Let your foot brush the ground: holding your leg "ready" will only topple you over. The leg is heavy.
Think of your free leg as one of those wristbands that SNAP around the wrist. Your thigh makes contact, and the lower leg wraps from that contact down through the entire leg, and then releases. If you pick your leg up and try to gancho, the effect is not the same. Risk making a sloppy gancho rather than a tense one!
Above all, focus on your axis and stretch of the body: the strength of your axis makes the free leg's movement even more dramatic. It's not really about the gancho; 80% of your work is always about keeping your axis.
Last word of advice: keep breathing! A leader can't do anything with a stiff board as a follower.
Leading ganchos from overturned back ochos: let disassociation work for you
Disassociation, controlling the twist in your body so that hips and chest can maintain different angles, is the most important aspect of preparing to lead a follower's gancho. Disassociation allows you to stabilize your hips and use your torso to help the follower pivot.
I originally learned to lead these ganchos from turns, but many followers don't have strong enough turn technique to make this work well. I suggest: salida, (leader changes weight), one or two back ochitos (tiny ochos) to get the follower's hips pivoting, and then leading a stronger pivot to overturn the follower against your body, ready to gancho.
Stabilize your own hips: if you pivot the follower using your hip motion, the follower gets less of a pivot. When I follow, I prefer less torque but with stable hips. If the leader's hips turn, I get less help from the leader. Also, it brings the follower closer to the leader's body, so that the leader doesn't have to fish for gancho placement.
Adjust your angle AFTER the follower's pivot. I want to be facing perpendicular to the follower if I am going to do the gancho with the "same" side leg (i.e., using my right leg to lead a gancho on the right side of my body). I want to be facing opposite the follower if I am using the "other" leg (i.e., using my left leg to lead a gancho that was originally on my right side). Hint: I can sometimes get a secondary adjustment to the follower's pivot after I adjust myself.
Place the follower's back cross step/foot BEFORE placing your foot and ankle for the gancho. For best placement, turn your leg out at the hip, and lift your knee so that your leg is in an S-curve shape. I find that I usually get my little toe down on the ground, but I focus on connecting my instep with the follower's ankle, so that I know the location of the follower's axis/balance point. When I use the "other leg" I am aiming the back of my knee/thigh towards the spot where the follower is standing.
Keep your hips back over the support leg. Otherwise, the follower will not have space to allow the free leg to hook with your leg.
Continue to twist your torso around your own spine and rebound back to neutral in order to lead the follower's free leg. This not a wrestling match: don't pull or push with your embrace to make something happen.
As the follower's leg completes the gancho, gauge the space you have to move, as well as the force of the gancho, and use that energy to create the next step in your dance.
The principal error I see on the dance floor, is to make the gancho a move about momentum. True, a good gancho can be fast and snappy, but a slow-mo gancho feels better to me as a follower, and is no less of a hook. The gancho is about TIMING.
The best exercise I have ever seen to practice ganchos comes from Chicho Frumboli. In his teacher training workshops, he had us practice ganchos, without using an embrace (balance work), in slow motion (timing practice), over and over (motor memory). By the end of the two-hour intermediate class, followed by the two-hour advanced class, my brain was fried, but I really understood how this move works!