No doubt fullness makes you dull, lazy or tired. So avoid making stomach full of liquids or solid. All work and no play makes Jack a dull boy. It's true more in real life actually and especially when it comes to hunger of sex or romance or exercise etc. So avoid being on the seats all the time and kick your buttocks every now and then. Stop watching whatsapp, Facebook, TV, etc (impotent makers!).
Yoga Pranayam has absolutely no substitute and mind you only early morning 5 to 6.30 am is the best for it, if you want to remain sexy.
Porn has already made 70 % watchers totally impotent and drinks, foods, smokes, desserts, pastries add to it. And the packed chocolates ice-creams, fruit juices make it all more worse.
Be on your toes, flex all too much, squat often, use Indian toilet and avoid servant's help all the time. Sexercises are to be learnt personally for your own fitness. SO remember, keep stomach and bellies light or you'll lose your flight.