ok...use lots of lube and go slow, warm her up to it all the way, start off vaginally so she's horny and therefore more into the idea of anal...when she's ready to switch, pull out and start playing with her anus, rubbing, gentle fingering, licking etc, use this time to get her lubed up as well...after a bit slip a finger in and work it in and out slowly, then, if you feel like, add a finger...if she has an anal suitable toy she likes (which it sounds like she does) slip that in and work with that a bit...when you two are ready for your dick to actually enter make sure you're all the way hard and lubed up yourself and pick a position she's comfortable with, missionary works great as does doggy...press the head of your dick gently against her anus and increase pressure slowly until you feel your dick slide in, it'll happen somewhat suddenly...go in til the head of your cock is inside and pause, communicate etc, if you get the 'go ahead' work it in another inch, pause, slide in and out a bit then go as far as she's comfortable with and fuck her softly until she's ready to take it harder...it's very important to make her feel comfortable and like she's in control of the situation so communicate...if she says stop, then stop, don't guilt her or make her feel like shit for not being able to take it if she can't...it may take several tries for her to take it like you want anyway...if it hurts her you're doing something wrong, so slow down, add more lube etc, there's no reason for her to feel any significant amount of pain...all the horror stories floating around about anal exist only because of people doing it wrong, as far as cleanliness, if she's taken a good crap earlier that day you shouldn't have any issues, a condom would still be a good idea if you feel squeamish about that plus, infections aren't fun...i dunno, i've never had any problems without one but it's still a good idea :2 cents:
have fun :thumbsup: