1082: Geology
Image Text
That's a gneiss butte.
Explanation
Here we have Cueball and Megan (with her stylish Geology hat) discussing Geology and the words they use are ripe with puns and double entendres which also have sexual meanings. In the end they just decide to get it on. (On top of the rocks, which much be not that comfortable.)
In the alt text, "gneiss" is a type of rock (apparently pronounced "neice", as in a relative) [1], and "butte" is "a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top" [2].