If I wanted to trademark a tagline "We make you happy inside!"?

Question

How do I do this?

Answer 1

Are you making a food product, or maybe a device for females to give themselves pleasure?

Answer 2

Use a legal federal trademark service. Here is a resource you can use. They have a phone you can call to ask questions.

Answer 3

see an intellectual property attorney.

choose a good one and pay the cost. the poor ones aren't worth hiring at all.