The short answer: no, this quote doesn't appear in the book.
To prove that to yourself all you have to do is an experiment, you need to download a neat searchable version of the book anywhere online, open it in Chrome or any PDF reader, Ctrl+F or Cmd+F, and attempt to find the quote. One can see that:
The word hamster doesn't occur anywhere in the book.
The word cave doesn't occur anywhere in the book.
The verb pucker doesn't occur anywhere in the book.
The term legged young doesn't occur anywhere in the book.
Moreover, this quote seems to be extracted from Re-Living The Dream by member 87JPR87 rated Fiction M (Mature) published on fanfiction.net:
''What? It's good!''
''More like Fifty shades of awful...'' She mumbled, idly flipping through the pages, snorting as she read through it. ''Listen to this; 'His pointer finger circled my puckered love cave. "Are you ready for this?" he mewled, smirking at me like a mother hamster about to eat her three-legged young.'...''
Bryan snorted loudly opposite her as the rest of the table descended into laughter, Alexa continuing her rant.
''Puckered love cave? I mean, what the actual fuck? I've read better stuff on a bathroom stall... 'He's going to kiss me there!'... 'He gives me a wicked grin, the effects of which travel all the way down there'.. Clitoris! Just say it!''
It is clear now that the quote is fictional.
Therefore, this quote is fake and does not appear anywhere in the book.