there are times where I regress so strongly that I feel more infant than adult. I take a baby bottle very naturally and I can play with infant level toys easily and for some time. the same with childrens TV. I know a lot of others like that where the regression is very strong and the experience of being infant is very authentic. I have a good collection of baby clothing which I wear and it will often just feel 'right'. As part of keeping my baby needs under control I spend every night in baby nightwear with dummy and of course, a sleep buddy (my teddy).
Everyone is different, but there are a lot of people where the desire to be a very very young infant is overpoweringly strong.