I've developed a novel way of simulating anal sex when on your own.
Firstly, roll up two bath towels and insert one into each leg of a baggy pair of jeans. Then add a pillow to the crotch of the jeans, and dress the top if the pillow with a long-sleeved shirt. Stuff each sleeve with a smaller rolled towel; you have your 'arms' and 'legs'. Shape as required.
Next, get hold of a toothbrush-one with a rounded handle, preferably with soft rubber ribs (be sure nobody plans to use the brush!). Wedge the bristle end of the brush either into the tightened zip of the jeans, or between the buttons of the fly. Secure on the inside with tape.
Undress, and apply Vaseline to the end of the toothbrush and around the rim of your anus. 'Mount' the clothed figure (I love facing upwards, wrapping the 'arms' round my waist tying the sleeve ends together as an embrace) then slide your anus to the toothbrush. When the handle presses your ring, gently ease yourself along it for an inch or two.
Thurst back and forth, playing with your cock with a spare hand.