In this group sex act, one man penetrates, or "doggies," a woman from behind while another gets a blowjob in front. During their exertions, the man--jubilant over their good fortune--reach up and high-five each other, thus forming an Eiffel Tower-like shape with their outstretched arms.
from the book: Dirty Sanchez's Guide to Buck Nasty Sex
Bro 2: "Bro, I know, bro!"
Bro 1: "Bro, we should high-five, bro!"
Bro 2: "Bro, we should double high-five, bro!"
Bro 1: "Bro, like an Eiffel Tower, bro?!"
Bro 2: "Bro, definitely, bro!"