Was it so late, friend, ere you went to bed, That you do lie so late?
Faith sir, we were carousing till the second cock. And drink, sir, is a great provoker of three things.
What three things does drink especially provoke?
Marry, sir, nose-painting, sleep, and urine. Lechery, sir, it provokes and unprovokes. It provokes the desire, but it takes away the performance. Therefore, much drink may be said to be an equivocator with lechery.
I believe drink gave thee the lie last night.
That it did, sir, i' th' very throat on me; but I requited him for his lie, and, I think, being too strong for him, though he took up my legs sometime, yet I made a shift to cast him.
Macduff had just arrived in the castle and noticed something odd about the porter; he asked him if he had gone late to bed. Porter tells him he stayed up drinking until 3am and how it makes him do three things.
Macduff asks Porter what three things drinking made him do and he tells him it made him urinate, turned his nose red, and made him sleep. Porter also tells him how drinking can bring exotic dreams, but brings consequences which aren't the best.
As Porter explains the consequences that comes with drinking, Macduff tells him he assumed alcohol made him go through this last night. Porter admits it did and even made him unsteady , but says he then threw up, which made things better.