I've had some success using this against Snake's grenades. Sometimes it's not possible to pick up grenades with enough time, since some Snakes like to cook them a bit before tossing, but I've noticed that it's more popular to throw a preliminary grenade out and then cook a second. Either way, if you pick up a nade and glide toss forward while throwing it back, you don't get caught in the explosion and you're squared up for a double bair. If you were too close, you slide through him and can just grab him from behind. Both are nice set ups for the easiest spike known to man.
Again, this can get real ugly if cooking another grenade since you'll just explode upon kick and then get jab comboed. I think it works well enough to be used once in awhile, though.
I think generally when I glide toss I throw backwards so I can quickly double bair. Against shorter characters (read: Diddy), I throw forward and follow with a dsmash or fsmash as TechnoMonster hinted at. Definitely a neat technique for DK.