"Undie Twinks" is a term used to describe young, slender, and usually scantily clad male individuals who are involved in gay pornography. The term "twinks" refers to the youthful appearance of these individuals, typically in their late teens or early twenties. In this context, "undie" suggests that they may be wearing underwear or other revealing clothing, often highlighting their athletic bodies and attractive features. This tag is meant for adult audiences who are familiar with and interested in gay pornography featuring young, fit men.