Sounds like it might be a combination of a few things. First you have to loosen up that soleus. Focus on the lower part of the calf when you do any lax ball or barbell smashing. Also, make sure you spend a good bit of time mobilizing the bottom of your feet. This directly has an effect on your soleus. Lastly, use a lax ball to get into your peroneal muscles. This is the muscle group on the lateral side of the calf. Most likely this is what is snapping over the side of your ankle. 

Good luck,

Danny

MWOD Coach