Dildos or dongs come in a variety of sizes so you will have to do some experimenting with how deep and wide you like your penetration.  Many dildos are made of silicone because it retains body heat and is easy to clean.  Some less expensive dildos are made of rubber.  You can even get dongs made of glass. Those tend to be a little more expensive but have the benefit of being able to be warmed up by placing them under hot water or even put in the refrigerator for a while without damaging the material.  Some dildos are fashioned after real cocks and are realistic looking while others are seamless and smooth.   You will notice dildos designed for anal use are flared or larger at one end, sometimes with a flat base to ensure easy removal.  For penetrating your partner hands-free, try a strap-on harness where the dildo is places in the harness and is to be worn by one lover while penetrating the other.  Some even come with a built in grip handle at the base for better control.  Double penetrator type dildos are made for two people.  They are usually two realistic dildos joined at the base with a little extra wiggle room in the middle. 

To make it even more interesting, some dildos are cast from famous adult porn star penises.  Now, if you have always wanted to do Ron Jeremy, you can go buy a dildo made from a mold of his actual cock!  Or maybe you are looking for the perfect dildo gift for your long distance lover, get a dildo-making kit and cast a dong straight from a mold of your penis.  Now they can be fucked by you even when you aren’t there!  Suction cup mounted dildos are extra fun.  Simply mount them to the floor, wall or bed post.  You can get them to stick to practically any flat surface. 

Another type of dildo is the penis extension.  The strap-on type extension has a hollowed out, rigid, realistic looking penis that utilizes straps to stay on and add some girth and length.  The strapless models roll on like a condom and add a few extra fleshy inches at the head.  Everybody’s a winner!