SMD is an acronym used in texting and online communication. It stands for "suck my d*ck" and is considered vulgar and impolite. The interpretation of the phrase depends on the context in which it is used. It can be used to express anger or as a lighthearted comeback. Other meanings of SMD include "surface-mount(ed) device" in electronics, "Sega Mega Drive" in video games, "Social Media Douchebag", "Small Mans Disease", and "Simian Mobile Disco".