Muscled Suid Bulges are common materials in Xenoblade Chronicles X. They can be obtained from Suids in Primordia. This item can be exchanged with 30 Reward Tickets from the Network Console in the BLADE Barracks.
Obtaining them is easiest at Starfall Basin and West Gate Plain. Clearing one area and then fast traveling to the other will reset the previous area and can be done continuously. Suids appear only during the daytime.