Start by doing a Delilah mount on the hoop, which is similar to a side mount. Hold on to the bottom bar with your hands facing each other and hook one knee on the bar. Then let go with the same hand (ie if your left knee is on the hoop, let go with the left hand) and extend. You can also grab your back foot with your hand from either side, depending on the effect you want to achieve.
A variation called open Delilah is when you hold on the the hoop only with the same side hand as knee (if your left knee is on the hoop, holding on with the left hand). You can extend or grab your other foot here too.
A harder variation (requires more back bending) is to do Delilah on the top bar :