I've done enemas and colonics for many, many years, and like different levels and types of clothing depending on my mood, setting, and partner, and interest in different types of added kink. I've done them solo for about 10 years now, and alone in the bathroom on a thick bathroom rug, I always wear sneakers +/-socks, both to keep my feet warmer, give me better stability when I need to stand to look at distention or to walk to the commode with a large water volume/mass inside trying to change my center of gravity. Also, I have a longstanding sneaker fetish and the arousal from wearing them improves my orgasms. I also wear sneakers during commercial colonics for he same reasons.
If the sneakers I choose for the day plus the enema give me enough erotic stimulus, I'll just wear a t-shirt or flannel shirt to keep warm during an enema. Or since I also have a rubber fetish, I often wear various pieces of latex rubber or neoprene clothing to increase my arousal and orgasm production, which may include a latex full catsuit plus hood and gloves or a partial neoprene rubber exercise suit or wetsuit before putting on my sneakers. At a commercial colonic appointment I usually just wear sneakers and normal non-rubber clothes as I haven't quite developed the courage to ask the colonic therapist if I can wear rubber clothes with my sneakers, as much as I'd like to.
When my switch Domme ex-GF or ex-wife was giving them to me years ago, she loved stimulating me not only with the enema but with as much other kink as she could include along with it. Usually that meant latex catsuit plus hood and gloves with heavy rubber sneakers on my feet before the enemas started. It also meant prolonged large enemas while restrained with frequent edging and variable orgasm denial until the end of a 2-3 or even 6-8 hour enema retention with me as long-suffering and complaining enema sub. We both loved all those various aspects of them including the D/s, rubber clothes, sneakers, prolonged distention and embarrassment/humiliation. These days I try to emulate those greatly erotic and satisfying kink enemas when doing it all to myself.