Can I buy a strap on harness for my double dildo
Some strap ons come with integrated double dildos, so basically a double dildo with a harness. U-shaped double dildos (that points in the same direction) that have a suction cup base can be used with some harnessess if you have a o-ring that fits with the base. But try and find one, that already have a harness attached if you are interested in this, as it is not certain that it is compatible.