I suggest Polyurethane condoms which are now quite thin, easy to use, and have quite sufficient stretch. Latex, even with good lubrication, still has a tendency to tug slightly at delicate membranes, and the mucosa of the colon are pretty delicate. Whatever you decide on, move gently early on, relax, and make clear what you are going to do or want.
So, go to it and enjoy ! !
P.S. Any chance of Kiss n Tell ?