Honey skip, named after its discoverer Honey, saves about 15 seconds by skipping the cutscene of finding the Bowser sub at Pinna Park. It can be very difficult at first, but does have good visual cues. I wouldn't recommend learning this until you have a time of 1:40:00
Why it Works
In SMS, most cutscenes can be skipped if Mario dies on the same frame the cutscene starts (1/30th of a second). With this setup Mario's angle (the ledgegrab camera align), forward/backward position (the outline), and horizontal position (visual cue) are the same every time. Another mechanic is that if Mario is on an out of bounds floor for a certain period of time he will die. So, if we sidestep at the same speed (full speed) from the same position it will work every time
Clipping into the Building
The seam between the roof and wall of the building isn't very good, so if you hover forward into into it you clip straight in. To make sure you hover at the right height, start a bit below the seam. Mario will then be pushed up from hovering and clip in. While inside the tower, dive and then groundpound to get into the shorter building. Do not move the camera horizontally. After clipping in go to the close right corner of the building. This corner is the only one you won't die from standing on. To get there hold the direction while in mid-air since this won't change Mario's angle.
Fun fact: Mario doesn't die in this corner because he is standing on the shadow of the tall building, which has a thickness of 2 units and technically counts as a floor.
Brightened for clarity
Executing the Skip
When Mario is close to the closest wall, he will not have a dark outline. As he moves more forward he will get one. Position Mario as close as possible to the wall while still having the dark outline. Next, sidestep so that Mario is in the position he is above. His hand should be not quite touching the white splotch on the edge of the brick (circled in red). Be careful not to go too far to the right or you will clip back in bounds. After Mario is positioned, hold neutral and hover until Mario's head touches the red line. There is a light spot in the texture theat goes a bit farther left than usual which I use as a visual cue for this. Once his head touches, groundpound and hold L and Left. This will sidestep Mario onto a death floor and he should die at the exact time the cutscene starts.