“I save my back exercise till the end… lats but not least” was posted on Twitter by Dubai Dad Jokes on May 15, 2023, and then posted about a minute later on Reddit—Dadjokes.
 
“Lats but not least” is a pun on “last but not least.” “Lats” (Latissimus dorsi muscle) is a flat muscle on the back.
 
   
Wikipedia: Latissimus dorsi muscle
The latissimus dorsi (/ləˈtɪsɪməs ˈdɔːrsaɪ/) is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: latissimi dorsi) comes from Latin and means “broadest [muscle] of the back”, from “latissimus” (Latin: broadest)’ and “dorsum” (Latin: back). The pair of muscles are commonly known as “lats”, especially among bodybuilders. The latissimus dorsi is the largest muscle in the upper body.
     
Twitter
Dubai Dad Jokes
@DubaiDadJokes
I save my back exercise till the end…
lats but not least
3:06 AM · May 15, 2023
 
Reddit—Dadjokes
Posted by u/dubaidadjokes May 15, 2023
I save my back exercise till the end…
lats but not least