I had something like this...used a little dollar store journal and covered it in stickers.
Okay, I'll admit...I didn't want to draw attention to the fact that the journal pages had little snipits from cosmo and written in tips from some books.
It wasn't a dedicated "sex" journal (althought that's mostly what I used it for) and I made the mistake of using it to record an important phone number in for my boyfriend. He lived 2 hours away with his grandparents at the time and I accidentally left it behind after visiting. Well...he left it out on his computer desk not realizing what it was and his grandmother found it and took a look through it!!! I'd only visited a couple of times before but she was quick to tell my bf that I was the wrong girl for him with very perverted ideas! LOL
Still with him (4 years this May)...guess he took a look through it too and decided to keep me!!!
My advice....don't leave home WITH this!