There are lubes that have MINOR muscle relaxants in them which can help but you must use a condom or they ten to make the guy penetrating go flat plenty of lube also remember your average dildo or but plug is harder/firmer than a dick even a rock hard dick has give. also cheap dildos use a condom over them because the tend to have imperfections which can cause scratching similar to fingernails. go slow make it easy and by yourself do something that makes you really horny or pulls you out of your mind a bit alcohol (small amounts get you to tipsy or auto-erotic asphyxiation or go on a HARD LONG run) help in the beginning they take away a lot of the apprehension that can cause tensing and tightness make sure to masturbate while your using the dildo or but plug or your fingers the first time. Douching not in the shower but with a bulb is a great way to train your muscle to relax and tense on command also helps loosen you and get used to the feeling of something inside you USE WARM water cold is a fucking shock and quite frankly AWEFUL. Now as far as soap goes if you use any you don't have to make sure its an enema soap as regular can dry out the mucous membranes and make it itch dry and painful. small vibrators help to loosen you up in the beginning. Do not use a numbing agent like anal ease until you are aware of your limits afterwards use at your discretion. Porn or hell your favorite tv show with hot guys can distract you and allow you to do the initial penetration and discomfort without issue.