"Built for comfort, not for speed" is a reference to the size of the person you are having sex with. A heavier person is easier to rest on or ride on during sex, thus "built for comfort" for a long session. A skinnier partner is better for a quickie, thus "built for speed." The latter is referenced in Little Richard's "Long Tall Sally," a tall and skinny girl (or crossdresser who is bald) who is "built for speed."
This is also the derivative of the term "spinner," a small and thin girl who can literally be spun while on top.
"Built for comfort, not for speed" is a reference to the size of the person you are having sex with. A heavier person is easier to rest on or ride on during sex, thus "built for comfort" for a long session. A skinnier partner is better for a quickie, thus "built for speed." The latter is referenced in Little Richard's "Long Tall Sally," a tall and skinny girl (or crossdresser who is bald) who is "built for speed." This is also the derivative of the term "spinner," a small and thin girl who can literally be spun while on top.