Complex sentence: Such tattoos have become popular since the late 1990s, but they are sometimes derided as suggestive of promiscuity and often referred to as "tramp stamps" and other slang terms.
Split into simpler sentences: Such tattoos have become popular since the late 1990s. They are sometimes derided as suggestive of promiscuity and often referred to as "tramp stamps" and other slang terms.