I'm a devout cocksucker so having a rock hard boner aint that important to me. Boners are few and far between these days, and I take Viagra or Cialis only to show my partner that I am turned on (some guys like to SEE the proof). Both give me headaches the next morning.... I have not yet purchased sildenafil from Blue chew or on of the other online places, but am researching to see which is the best outlet.... Not sure why someone would want or need a 24 hr boner ? But hey to each their own, ENJOY.