I am also new to anal play and have tried various plugs. The Bootie is actually just a tad too big for me to insert comfortably (though it is comfortable once inside).
The Tantus Small Flirt is easier to insert, but doesn't stay in place as well when you move around a lot.
The absolute best plug that I have found that works for me, as an absolute beginner, is the LELO Bob. IMO, Bob's the best, hands down. It is slim enough to insert fairly easily and is also EXTREMELY comfortable once inside.