any of the 'b' moves are good for desyncing except belay for obvious reasons. smashes, tilts, and taunts help too. learn to vary.
what i commonly use:
bliz -> SH bliz: ok for advance / surrendering
IB -> foxtrot IB: great for advancing
IB -> hyphen smash (dash + u-smash): use more than I probably should, timing can sometimes be tricky.
bliz -> grab: works better at low %
u-smash -> SH u-air :to move while on ground while opponent in air, juggles well.
squall -> squall: a.k.a the squall carry, before opponent D.Is you should end with either a:
squall -> grab (grab around middle of squall animation may need to dash grab)
squall -> smash (same as above w/ smash)
smashes
taunts (side -> up -> side = personal favorite) make sure you have time for it!
take your pick there are a few more I'm probably forgetting. takes a while at first to get the hang of chaining different desynches together, but there is almost a rythme you'll get after a while. The trick is variety. I think that the ICs have 4 games non-desynced, Desynced, grabs, and popo solo. Desynced is the one you will probably playing the most since it blends with grabs and needed for the start. The others are important but this is like the glue that binds all together. master it to master IC.