Yeah, I always wondered why people referred to it as "flat," because women aren't truly flat either. They don't have a big genital bulge, obviously, but there's the mons pubis, and some women do have bigger vulva than others, too.
I actually wore a girdle rather than tucking. It provided a little reinforced "shelf" to rest everything on, which meant that a) my mons pubis was still visible and normal and b) if anyone did have weird questions, "I'm wearing a girdle for tummy control" would be a perfectly normal answer for a cis woman too.