At the bottom on the chain (just off the sprocket),,, I spray the lube on the inside of the chain. This way the lube has to penetrate the chain and travel through the it in order to get flung out and onto my undertail. I lube my chain every 150 miles or so and never have a problem with lube crud getting on my under tail.
While the chain is hot just after a nice ride I put the bike up on the Pitbull, place bike in first gear with high idle on, hold a towel under the chain and spray lube, let it run for a few seconds and done. No wiping off chain and the chain looks clean all the time.