DTF is an explicit abbreviation meaning someone is open to sex, often in a casual context.
DTF
Down to have sex
Plain English
DTF: Down to have sex.
It states physical intent but says nothing about timing, attraction, boundaries or whether the person wants a one-off or repeat connection. It is more direct than terms such as open-minded or casual.
How it may appear in a profile
“DTF if the attraction is mutual.”
“The profile used DTF to signal direct physical intent.”