Preston's presents are often unhelpful -- unnecessary, ridiculous or inconvenient. However, he always gives out of the goodness of his heart, so it's hard for other people to get angry with him.
Preston's debut, Episode 2616, is an extended spoof of The Music Man. Preston's clothes and his persistence in giving gifts (rather than conning people) spoof the musical's title character, Harold Hill. His name is a take on Robert Preston, the actor who originated the role on Broadway and starred in the film version.
The puppet would later be re-used on Sesamstrasse in various roles, mainly as a salesman, such as Reiner Sauberhasi, Knut Köffelström, Hasi Himmelglück, Armin, Henry, an unnamed audience member on Eine Möhre für Zwei, as well as on Die Große Sesamstrassen-Gala, and again as a rabbit named Preston on Sesamstrasse, and for a series of 40th Anniversary live puppetry workshops for children held at venues all over Germany in 2013.