You can see how I lay a stem tightly against the bouquet handle, allowing the top to bend and "disappear" in among the leaves.
I could just bunch the stems around the handle and tape. But I like to make sure my stems lay properly and conceal all my mechanics. It's easier if you use floral clay wrapped around the handle to press the stems into and hold them in place before wrapping with florist tape.
Just peal off the outer tape wrapping and stretch the clay around the stem of the holder, starting high at the top.
Wind the sticky clay down the bouquet handle.
Lay your cleaned stems against the clay, pressing lightly into place. Add more stems until the handle is completely concealed. Wrap florist tape around the stems, stopping a little less than halfway down the handle.
Start the florist tape high under the leaves, taping over the cut ends of the stems. Pull the tape as you wrap around the handle, which will make it stick to itself and create a tight bond.
The stems may be uneven at the bottom. You'll need a pair of pruning shears or bunch cutters to cut them off in a smooth cut.
Grip tightly together, using the bunch cutters to give clean cut. You can also place it down on a cutting block, cutting through with a large smooth knife if you don't have bunch cutters.
The final stems should be long enough for a finished wrap with the stems down below and showing. Extend the stems a little beyond the hidden bottom of the bouquet holder.