Throughout the rest of the season various items can be seen with the question mark stickers on them.
When Nadia was trying to diagnose Tom, she was questioning if there was glitter after touching Tom's neck. That may be a reference to Ms. Knope Goes to Washington (2012), where Tom came up with the idea of Sparkle Suds.
In the scene where Donna is informed that she accidentally sent out an inappropriate personal tweet from the Parks & Rec Twitter account, she mentions an effective neck-massager, which in reality is a specialized vibrating sex toy.
Tom talks in a British accent to Nadia, who is played by Canadian actress Tatiana Maslany. Maslany, using a fake British accent, starred in the BBC America show Orphan Black (2013), in which she plays a British woman named Sarah Manning. Aziz Ansari, who plays Tom, is a huge fan of that show.