when using anal play i would recommend using "finger cots". you can buy them from lovehoney and other places like ebay.
they are latex and are designed to fit your finger, obviously.
i buy them from lovehoney, there is 200 in a pack.
i get clients to use them on me if they finger me (only for guys who have nails who insist on fingering)
and they are great for anal play. i don't offer it in my professional life but in my personal life i do a lot of anal play with my long term partner.
for smells, i used to work in the hospital, and as you can imagine, i came across a lot of smells. from vomit to poop to blood.
sometimes smells get stuck in your nose. they can get stuck in your nostril or nose hairs. i trim my nose hairs regularly. and i use chewing gum to try and clear my nose. if that doesn't work, i use my nose spray
(first defense spray). it wont harm you. and it will definitely take the smell away (unfortunately you will be left with the smell and taste of first defence, and although it isn't great, its better than poop)