The Los Angeles Metro sparked a social media frenzy on Thursday after unveiling “Ride the D” merchandise — a slogan with an unmistakable sexual double entendre. The black “Ride the D Unisex Heavyweight T-Shirt” features the phrase “Ride the D” printed across the chest in white lettering, with the “D” styled inside a purple circle — a nod to the transit agency’s D Line branding. The shirt, which retails for $21, is modeled on the product page by a young man wearing the black tee with light gray