You can hike to the cove but its best to take a short banca ride from Tambobong. On the way to the cove you will be passing by a small island whose one end resembles a semi-submerged crocodile head.
Inside the cave is a nice emerald green pool about 8-10 feet deep at its deepest. There are several entry points to the cave : there are two easy ones on the beach, another one is on top of a hill above the cave where you can jump straight into the pool, and several entry points submerged under 4-5 feet of sea water. (Btw, some of locals fondly call the cave "The Baby Factory" :D )
Caves like this are pretty common along the rock walls of Pangasinan's west coast. The photo below shows a typical rock wall along Sitio Pedeg.
There are sporadic beaches in between these rock walls (like the Cabacungan cove). When the waves are strong you will be able to see the columns of sea water surging up the blow holes. Because of these blow holes its common to see white sand deposits on top of the rocks, particularly those in Sitio Pedeg.
More photos here.