The pork butt and the pork cushion are both from the pork shoulder …the upper 1/2 is the pork shoulder Butt # 406 and the bottom Half is Pork Shoulder Picnic…AKA Cushion # 405.
The "cushion" comes from the Pork Shoulder Picnic (or Arm), The picnic shoulder is more economical than the Boston Butt, but also contains more fat than the blade shoulder. When the bone and fat is trimmed from this cut it results in a very rich flavored roast. The meat from this cut is excellent for making juicy barbecued pulled pork. The Picnic has a large bone and joint that runs through the middle of the roast, one side has a large lean muscle...that is the "cushion". You can also slice and pound them for pork cutlets, stew meat, etc and use them in any chicken recipe.
The 'whole' pork shoulder (15-20 lbs) consists of the upper part (Boston Butt) and the lower part of the shoulder (the Picnic). You can purchase it whole, however most times it is found in the store separated into the two pieces mentioned above. The difference between Picnics and Boston Butts are the bone structure......the butt has a small shoulder blade bone and the picnic has the front leg bone and joint. The
picnic is normally sold with "skin on", whereas the Butt only has a small fat cap. Both have excellent bbq meat, but the Boston Butt has the better value.