Basically, there are only a few things that can cause a throw to whiff, and most of them are reactable and unsafe, as such you should be watching for a punish for these things during every throw you do. Meaty throws are special compared to normal throws because you'll be reliably point blank and you'll have a few extra frames of play for your punishes. The "OS" part of this comes from the fact that your throw attempt also punishes jumps and v-shifts.
