There are no ‘best’ or ‘ultimate’ positions, just the best positions for you.
All vaginal sex positions can be adapted into comfortable anal sex positions.
Here are a few old favourites sex postions, re-invented for anal sex:
Recommended for anal sex beginners - Hop on Top
Receptive partner on top, which allow her/him to set the pace for anal sex and take as much depth as he/she is comfortable with.
This position is great for eye contact, communication and stroking. Also try the reverse cowgirl/cowboy position ( receptive partner on top but facing away) - visually very hot for your partner!
Lie back and enjoy anal sex - The Missionary Position
The receptive partner lies on his/her back with knees bent up – the insertive partner on top.
Perhaps try a pillow under the bum for ease and comfort and, if you're nimble enough, legs over shoulders for a better angle...
This position is best if you are experienced in anal sex and have trust and communication between you.
The receptive partner doesn't have much control of pace, depth or moves, but she/he does have the advantage of comfort and the positions to simply lie back, relax and concentrate on the sensations.
Probably the most famous of all anal sex positions - From Behind.
Try lowering your head and shoulders as this creates the perfect position for G-Spot/prostate stimulation.
f you are using a sex toy with a curved upward angle to it - in the doggy position you should turn the toy so it points downwards - this will make it the "right angle" to hit the pleasure spots.