Telly's mom appeared on Sesame Street in Episode 2955 in which Telly was worried that he needed to give up his favorite blanket, Softie. At the start of the episode, a worried Telly tells Savion that his mom told him not to pack his blanket when he spends the night at his friend's house. Savion suggests that maybe Telly is too old to carry around a blanket, prompting another panic attack.
Telly's mom reassures her son that she didn't want to take his blanket away -- she meant that she thought Telly should carry his blanket, rather than pack it.
Telly's mom is also heard in the Sesame Street Caring for Each Other video "Telly's Blanket Fort", asking if Telly needs help with anything.