The full form of XXX can have different meanings depending on the context. Here are some possible full forms of XXX based on the search results:

• Hardcore Sex: This is one of the possible meanings of XXX according to Abbreviations.com.
• Kisses: XXX can be used as an abbreviation for kisses, usually placed at the end of a letter or text message, often alongside ooo (hugs) .
• Pornographic content: XXX marks something as pornographic, often used as shorthand for any sexual content.
• Roman numeral for thirty (30): XXX is the Roman numeral for thirty (30) .

Its important to note that XXX can have different meanings depending on the context, and some of these meanings may be inappropriate or offensive.