TWSS is an abbreviation that stands for 'That's what she said.' It is used in response to a statement that can be interpreted as having a sexual innuendo. The phrase has become popularized by the television show The Office, and is often used as a joke among friends or co-workers.
TWSS is a well-known and widely used texting abbreviation, especially among younger generations. It is often used in casual settings or among friends to add humor to a conversation.