Question about turning my girlfriend on??? need answers?

info- have girlfriend of 3 years... past few months she has been losing her.. nimfo**side.. she dosnt get excited alot anymore.. and not having so much......ok well last night my girlfriend spent the night... i desided to try something new... we were making out and i desided to and have her watch... we were sitting.. my legs around her weist... and i was jerking off like 5 inches from her face.. this got her very excited.. expecially when i med all over her... what other things can i do to make her excited again???? need help!!