It’s something quite common while learning the hip explosion on Snatch related exercises and even more experienced lifters can have this problem. Its a horrible pain when you catch your pubic bone. The reasons stem from two main factors; bending at the arms before the hip drive and having your grip too wide.
Bending at the arms is pretty self-explanatory. When your arms are bent before the hip drive you are raising the bar to a higher position so it’s more likely to hit your pubic bone. A lot of people when learning the second pull (the pull after the hip drive) tend to suffer the most with this. Correcting this can be easier said than done. Focus on keeping your arms straight on assistance exercises such as high pulls and transfer over the skill. Pulling straps will help you relax your arms as they take away the strain needed to grip the bar. Also, when you set yourself turn your elbows slightly in to hold them in place easier.
Having your grip too wide is again going to raise the bar, so when you hit the bar you’re going to hit the pubic bone. Instead, stand up straight holding an empty bar in Snatch grip and find out where the bar is aligned on your body. From there you can use that as a guide to adjust your grip to avoid hitting your bone.
If you find you are still suffering a small towel folded up in your skins or a piece of sponge should suffice.