What color is the sap? Is it gooey or thin?

Thin.

Sap usually flows heaviest when the sun shines on the cane directly. Standards have that thick, bare trunk absorbing all that heat from the sun, pushing sap upward in a steady stream, a much greater amount than most rose canes arising from the base of the bush can push. It's something I first noticed when heading back newly budded plants, removing the tops of the stocks above the healed-in scion (bud). I found the only thing which stopped the "bleeding" from those stock piece cuts was melted candle wax. Elmer's Glue is water soluble. Sap is primarily water. It dissolves and washes away Elmer's Glue. Pruning Sealer is asphalt. Sap flowing up the stem can easily inflate that rubbery petroleum product like a balloon and burst it, so it continues bleeding. But, melt candle wax over the cut end and it seals it. You have to coat it all over so every possible spot for sap to escape is thoroughly covered. For those real heavy "bleeders", you'll find if you make those cuts either early enough in the day or late enough so the sun isn't shining directly on the plant, the sap won't bleed as heavily and you can seal the cuts with candle drippings more easily. Once the sap is bleeding steadily, it can be nearly impossible to get anything to stick well enough to stop the flow.

Thank you RS. I knew there was a scientific gardening answer to this phenomenom I was seeing

You're welcome, a1an. I hope it helps.