When an angler catches a nicebass and holds it out towards the camera as far away from his body as he or she can stretch. All while grinning from ear to ear. Related to the "long-arm" but entirely different.
That guy on social media always does a Japan pose when he catches a bass.
During intercourse when in missionary, having your arms locked pushing down on a surface is called the seal pose. This is because you supposedly resemble a seal while going deeper into her
Her: damn u really in the seal pose right now?
Him: fuck ya im in seal pose it's better Her: you look funny asf