This porn video tag appears to be a reference to the actress "Lindsay".
The term may refer to several actresses in the adult film industry who are named Lindsay. These include:
1) Lindsay (last name withheld for privacy) - an American actress, active from 2013-2014. She made her debut in "Bang Bros", a popular porn website.
2) Lindsay Taylor - she has worked as an actress since the late 90s and is known for her performances in numerous adult films.
In a general sense, this tag would be used to search or identify content featuring any of these women.