First of all, in case you want to draw a greater accent to the wax, you can use ropes just to tie the bottom partner’s hands and legs or to fix them in a desired position. The feeling of not being able to avoid the drops and having no control over the area of impact can be very sweet.
The other scenario implies mixing of rope touch and wax drops. It is implementing wax candles to a shibari session. After making a desired tie pattern the top partner can drop some wax on the areas between ropes. This will add a very special feeling of an overlapped touch for the bottom partner.
There is also another, more complicated, variant of implementing a candle into a shibari session. It can be done during suspension. The rigger can place a burning candle somewhere between the rope strings above the bottom partner, so the candle drips constantly and on the one and the same spot. This creates additional constant dots of impact and a feeling of inevitability of hot wax touch.