At my work at Skookum Recycling Center, we are mandated to wear ear protection, either plugs or muffs, and usually they supply us with E-A-R disposable foam plugs (NRR 32 dB), but I had trouble using them because they were too soft, and also one of our co-workers during the summer put one in too deep and had the have someone pull them out with a pair of tweezers, and since I am more used to using (double-flanged) silicon eartips in my MDR-EX90SL IEMs, I decided eventually to use the Hearos Water Plugs (NRR 25 dB)
HEAROS.com for the same, more consistant feel as my IEM's. At first I tried Hearos Skull Screws (NRR 30 dB) at first, but found them to fall apart after about 2-3 weeks of rigorous use, so I tried the more-durable silicon-based Water Plugs instead.
Here's what I do with my plugs/tips, I just simply run the plugs through a small bit of warm water in the sink at work (not the IEM tips, just the Hearos) and when I put them in it goes in deeper and creates a very tight seal. But I myself would never put them in my mouth, (EWWW!!!) and while there ae various lubes and techniques that you can use, good-old warm tap water does the trick the best for me. As for removal (during ether lunch break or at the end of work), the Hearos Water Plugs have a 3/4" stem on the end so I can remove them easily, but I recommend you do that process
slowly beause if you pull them out too fast it could cause some minor issues with your hearing.