It basically means that someone will promote the other person on their own account in exchange for a cross-promotion. Snap for snap is a term used by a Snapchat user to request one person’s Snapchat account in exchange for their own, similar to the phrase “follow for follow”. This slang term can either be used to mean “shoutout for shoutout” or “snap for snap.” This piece of internet slang is commonly used on TikTok, Snapchat, and other social media platforms. According to Dictionary and The Sun, there are multiple different meanings for SFS.