I have tried the "butt into the seat" trick a few times and never been successful. What I have done...with good success 5 times now...is to use the centre-stand. What I do is make sure the back-side of the bike hangs over an area that is at least 3 inches lower than the surface the centre-stand is pivoting on.
Break the 5 lug-nut first...deflate the tire before removing as well. Just let the wheel "fall" out of the hub and down to this lower area. My favourite "drop" is off the back of my trailer which is about 6 inches above the road. The most times I have used this method is over a cement curb or the edge of a raised driveway. Also, as stated already, strap the centre-stand forward to something...I like the forward engine guards.
Works well and no removal of fenders or amp etc. YMMV.