What is the adverb for shenanigan?

There isn't a single, universally accepted adverb for "shenanigan." The word "shenanigan" is already a noun, referring to a mischievous or playful act.

However, you can use a variety of adverbs to describe the act of doing something mischievous, depending on the specific context:

* Mischievously: "He grinned mischievously as he pulled the prank."

* Playfully: "They were playfully teasing each other."

* Cunningly: "She cunningly managed to steal the prize."

* Deviously: "He deviously tricked his friends into believing his story."

* Waggishly: "She gave him a waggish wink as she told the joke."

The best adverb to use will depend on the specific type of "shenanigan" you're describing.