The heartbreaking reason why an aunt left detailed dog-sitting rules for her nephew Elaine Rios' dog, Pepper, helped her cope after her last dog died of cancer.

 -- When Tommy Rios watched his aunt Elaine's dog for the very first time he had no idea she'd leave him with a long list of do's and don'ts.

Rios, 20, who found the hilarious list -- which was printed and taped to the kitchen cabinet -- posted pictures of it on Twitter, where it quickly went viral.

Elaine said there's a reason why she's so particular with her 3-year-old Pomeranian named Pepper. The dog helped her cope with the loss of her late Pomeranian named Puppie Luv.

"He was my first Pomeranian. He was a special little guy and he passed away after 12 years from cancer," she told ABC News. "I got Pepper two years before he passed."

Elaine, 39, the sister of Rios' mother Denise, said Pepper helped her cope when Puppie Luv was receiving chemotherapy.

"It would've been much more traumatic," she said. But Pepper was a comfort, "because I did have someone to come home to after all of that."

So her nephew Rios understood when his aunt "planned for weeks" in order to leave Pepper with him at his mother's home in Fresno, California, when the rest of his family trekked to Disneyland in Anaheim.

"I was stuck watching everything," Rios recalled to ABC News. "And she goes, 'OK. I need you to come by the day before and I'm going to show you the list.' And I'm like, 'Wait. What?'"

Elaine had created a two-page list titled, "Pepper the most beautiful girl in the world," that included details on when to feed Pepper, what snacks she's allowed to have and issued reminders on how to show affection such as "big hugs little kiss, sniffs, belly rubs."

The list ended with "and most important ... don't you hate her cause you ain't her!"

Rios said all he could do was laugh. He later decided to post the list, with an adorable photo of Pepper, to Twitter that said, "just to show everyone how my aunt is."

When Elaine, who left on family vacation Monday, found out her list went viral, she took it in stride.

"It’s a little overwhelming, especially because I’m completely social media illiterate," Elaine said, adding that many dog owners understand her list. "Some of them are even asking to open an account for Pepper."

So far, she said she has no plans to follow through on that request.