Green’s Dictionary of Slang

(US black) a mouth seen as well-suited for the performance of fellatio.

2000		Ebonics Primer at www.dolemite.com 🌐 dsl (dick suckin lips) Definition: the type of lips a woman would have, that would be considered good lips for sucking dick. Example: Yo, that showty work at th’ licka stow got the D.S.L.!
2020		G. Krauze What They Was 108: She’s got them DSLs [...] I say what’s DSLs? Dick Sucking Lips fam.