What do these do or are they just useless items?Will there be new positions in the game, for example, lying next to you and fucking? 
Hi,
If you're talking about the items on the bedside table next to the phone, they just indicate what you've given to Yuna before that night, so there's the tea cup (after green tea), body lotion (...) and numbing chapstick (...).
As for other positions, right now there's missionary and doggy, dev has plans to add some more interactions, but I doubt he will add whole Kamasutra book, mainly because...well...she's sleeping...so some positions would wake her up... And that's not the point of the game right now.
Hope this helps,
Cheers