Make it a Crimson and Cream night
What I mean is this, that whole night you involve Deltas in the convo or evening, i.e. you read her some Love Poetry by Nikki Giovanni, watch a movie with Ruby Dee in it (or other DST actress), talk about some other influential Deltas who have impacted your life. Then you end it with how they are not the only ones to have affected your life, blah blah blah, will you marry me.
**this just came to me so I have not hatched it all out. But THEO dear heart, whatever you do show your sincerity and come back and tell us how it went.
**********EDITED*********
Cook dinner for her -- Crimson and Cream foods, i.e. Spaghetti, Red Kool Aid,

Red Velvet Cake and red and white jelly beans (YUM).
Have Crimson and Cream candles lit all around the house.
Have rose petals all over -- guess what colors?
Have a RED LIGHT SPECIAL.
Write a proposal poem to her.