No sense in pussyfooting around the issue. It's direct. It's short. It's simple.
How could anybody be possibly offended by this?
Try it out with your favorite prostitute first before you try it out around the house. Just so you can practice the perfect articulation of the phrase and get a few dry runs in. You don't want to bobble the pronunciation and look like some kind of tongue-tied rube.
For instance, where are you going to place the most emphasis? Is it on the "Suck" or the "Mine"?
Do you need to repeat the phrase over and over? Is saying this once to your partner really enough? What if your partner has been eating corn nuts earlier in the day and one is lodged in his/her ear? You wouldn't want them to miss this phrase. Work on your volume. Make sure you project.
What happens if you develop a stutter mid "Suck"? 34 years of no stutter and then one day—BAM—now you have a stutter. You don't want your partner confusing this phrase with an Indian dish because some of the transistors and connectors short-circuited in your wiring. Maybe see a doctor or a speech pathologist in the weeks leading up to the usage of "Suck Mine".
Practice. You think Martin Luther King didn't practice, "I have a dream"? This isn't improv night down at Giggles. Don't botch this. Lines this succinct don't come around everyday.