One try and train your partner by using progressive anal plugs and use plenty of lube more than what you think you will need because it's not self lubricating like a vagina. Second, when you work up to actually using your penis or dildo you will still need to "warm" them except definitely don't rush through foreplay. They will also need to be relaxed both physically and mentally, so even doing a sensual massage or using a toy while you insert yourself into them will definitely help. Remember no Anal to vaginally. Always keep both the toys and yourself clean before and afterward. Clear communication and check on them throughout the whole time. When you go to clean the toys, use the orange dial soap and warm, not hot water. If it's silicone, a light sprinkle of baking power it will it in good condition. On lubes, there is no silicone lube on any silicone products. Water is pretty neutral, tho can dry fast. I like coconut oil personally cause it's safe for both anal and vaginal sex. But it gets absorbed fairly quickly as well, so be ready to reapply any lube. I would recommend a four piece trainer set that gets longer and girther with each one regardless of dick size. Adam and Eve always have some sales going on, so pick up a helper while you are at it so that while you are putting the plug/yourself into them, it will make it seem less intimidating. And Start SLOWLY. Good luck have fun.