Milkduds are a popular modification of Elkmaster brand pool cue tips.
The Elkmaster is soaked/boiled in whole milk, and then compressed to a smaller
than original size.  The milk acts as a bonding agent or glue.  Elkmaster tips
are saturated with chalk as an OEM process.  The idea is that Elkmaster tips
have a playing feel and some think superior grip on the cue ball compared to modern
laminated pigskin tips.  The disadvantage is that Elkmaster mushroom with regular
play and must be maintained by constant dressing of the sides to be flush with the ferule.
The milkdud concept attempts to address this by pre-compressing the buffalo hide, giving 
the traditional playing control with modern low maintenance.  Some also feel that OEM
Elkmaster tips are too soft.  With this press, different hardness levels can be
experimented with by adjusting how much torque is applied while pressing.