I prefer to wear skirts, which makes tucking less of an issue. And HRT has made my male bits small enough that they aren't prominent at all. These days, even if I wear pants, a mild tuck in cotton panties does the job.
I do have a couple of pairs of quite stretchy skinny jeans that need some additional tucking assistance because everything is visible. In that case, I use a regular pair of firm control briefs. It does the job quite convincingly.
In winter, I wear yoga pants around the house. They are way too revealing to wear out in public. There is no amount of tucking that could get me to wear them out of the house. I might wear them to take out the garbage, but only because our driveway is in heavy forest and quite private.