This is just about as simple a tactic that can be considered. I've used it for years now. My Son & I have taken several bulls with it. This is a two person+ tactic.
There are situations where a bull will return a bugle to you, you stop & he stops, you can even wait for quite a spell & he will not bugle unless you do. I could go with a Slow Play Tactic here but these Call & Stalk tactics are fun too! -- With those bulls we will keep a Caller back to keep this bull bugling from 200-400 yards & out of sight, this shows the bull you're not pressuring him, the Caller will generally use a non-intimidating Location bugle in various volumes, kind of mixing it up a bit to sound natural & not predictable, he will bugle every couple of minutes as if in a conversation. The second hunter will now be the silent shooter slipping in towards the real bugling bull, no need for the shooter to call as long as the terrain allows for a nice stealthy stalk. -- The shooter should still be ready to scream a short bugle in case he accidentally bumps a cow or two on his way in, this can turn a fumbled situation into a tag punched!
This can come into play every now & then & the adrenaline & anticipation is pretty exciting for Caller & Shooter, each is hoping it turns out with a tag punched!
When a bull stays vocal on his own & holds his position then a solo hunter may slip in unannounced with a fair degree of success! I love calling bulls but tactics like this can present their own challenges as well with much satisfaction gained with positive results!