This has been discussed previously I believe.
The best method was to get a bunch of cable ties then line the inside of the grip with them, leaving the heads of the ties sticking out. This makes it fairly easy to slide the grips onto the bar and once its positioned just pull out the ties. If I haven’t explained very well maybe search for the previous thread where this was brought up.
As to the method of using an air-compressor, the trick for memory was to use a needle for inflating footballs etc. - stick the needle inside the lip of the grip and as you blow air ease the grip along the bar.
the air compressor i shall explain get the little air blower and place just under the end of the grip and air goes rushing in and you slide grip on that how i do mine but the cable tie thing sounds cool i have had back experiences with wd40 and hair spray all that stuff and dont use brake cleaner or start ya bastard as they are ethanol based and could eat your grip
air compressor works sweet, except for the last cm or so of the second grip
how do you get the last bit on? my right grip has been hanging off the bar for months
If you’ve only got a little bit hanging off the end, then you could try hitting it with an palm. It (kind of) works on cricket bat grips and I think I did it with my current bike grips.
WD40/RP7 works fine for me. I find high alcohol/fast evaporating stuff just doesn’t cut it. With the WD40 type stuff, a couple of hours and perhaps even some heat does help.
I prefer not to use water as I’m generally fitting them to steel bars.