This is something I read long, long ago. When it comes to anal sex, it’s important the receiver really wants it. Her/his heart must say yes in order for her/his asshole to open up to it.
And from personal experience I agree on this. My first wife told me she wanted to do anal with me. But max once a month. This didn’t really work, cause everytime she got nervous and clenched her spincter, causing agony and pain. When I told her the only way to get passed this, was having more frequent anal sex, she didn’t want to even hear about it.
So I stopped even trying at some point, cause clearly her heart didn’t say yes.
When I finally met this woman, who’s heart screamed “shove it in my ass please !” I dicovered the truth behind the saying in the title. My girlfriends’ asshole is always relaxed to receive my cock. After 3,5 years with her, there hasn’t been - not even one - an occasion where she couldn’t handle my cock up her ass. Her heart says yes every day and her asshole opens up whenever I want to go in. Even dry.
So for the people seeking an anal (only) partner: even if you find one, there’s still a neccessary emotionally connection needed to have good anal sex. Build trust, seek deeper connection, speak freely about desires and maybe the right person will cross your path.