This little hack came out in a DM session with our own, lovely @Christina , and she suggested it was worth sharing...
After lining your lips with your coloured liner, draw a second line immediately outside and next to that line with a transparent/universal lip liner. It provides an invisible barrier against colour-bleed, and it even fills some of the smaller lines around my lips. This is my go-to! ๐ฅฐ๐
Keep exploring the community!