Astronaut Jack while laughing says at :19 "Look up at me, look at my thumb". Astronaut Gene replies "I know, anytime you want to do something though"(Anytime the Astronauts need to get a better hand grip on something, they use their bare fingers).
At :32 Astronaut Jack has his arm outstretched, and the tip of his left hand thumb is seen through a cut hole in the tip of his work glove.
Astronaut Jack at the same time he is holding his left arm out, says at :31 "Big(Thumb) ah, portion of the Scribal(Hand) there you can see."
Pretending to be on the Moon, the Astronaut's spacesuits would have to be pressurized, naked skin can not be open to the outside pressure.
This video as you hear & see it, is located for download at NASA site:
Apollo 17 Video Library
Geology Station 3 at Ballet Crater
Journal Text: 144:58:45 RealVideo Clip: (2 minutes 15 seconds)
NASA did redacted editing & cleaning up of the text, to cover what they really said in the written records of the Astronauts conversations. Also in some video's NASA has later recorded different conversations, replacing what was originally spoken.
ALL NASA FOOTAGE USED IN THIS FILM IS PUBLIC DOMAIN. THE USE OF ANY COPYRIGHTED MATERIAL IS USED UNDER THE GUIDELINES OF "FAIR USE" IN TITLE 17 § 107 OF THE UNITED STATES CODE. SUCH MATERIAL REMAINS THE COPYRIGHT OF THE ORIGINAL HOLDER AND IS USED HERE FOR THE PURPOSES OF EDUCATION, COMPARISON, AND CRITICISM ONLY. NO INFRINGEMENT OF COPYRIGHT IS INTENDED.