SMF anal is something which only works if you both want it and both are comfortable. If you have any doubts at all then the best advice I can give is don't try it.
Don't allow yourself to be pressured or guilt tripped into trying something you are not 100% into.
If you do then start small, a finger with short well filed nail and no sharp bits of skin. Lots and lots of lube. Insert slowly a small amount at a time and wait before going further. If it hurts stop, breathe deep wait for the pain to go before pullng it out.
With toys start small, with something designed for anal play and slowly work up. It might take weeks or months to get to the point where you can comfortably have anal sex or you might decide it isn't for you.
Personally I don't like beads. a slim dildo or plug suits me better. But always slow and well lubed.