Here are some examples of slang or sexual language which were clearly understood by Shakespeare's original audiences, but may be less obvious to audiences today. These examples were put together by Heloise Senechal, from the Complete Works of Shakespeare (2008) published by the RSC and Macmillan.

FROM HENRY IV, PART II, ACT 2, SCENE 1

MISTRESS QUICKLY: Alas the day. Take heed of him: he stabbed me in mine own house, and that most beastly. He cares not what mischief he doth, if his weapon be out. He will foin like any devil. He will spare neither man, woman, nor child.

FANG: If I can close with him, I care not for his thrust.

MISTRESS QUICKLY: No, nor I neither. I'll be at your elbow.

FANG: If I but fist him once, if he come but within my vice —

MISTRESS QUICKLY: I am undone with his going. I warrant he is an infinitive thing upon my score. Good Master Fang, hold him sure: good Master Snare, let him not 'scape. He comes continuantly to Pie-corner — saving your manhoods — to buy a saddle, and he is indited to dinner to the Lubber's-head in Lombard Street, to Master Smooth's the silkman. I pra'ye, since my exion is entered and my case so openly known to the world, let him be brought in to his answer. A hundred mark is a long one for a poor lone woman to bear, and I have borne, and borne, and borne, and have been fubbed off, and fubbed off, from this day to that day, that it is a shame to be thought on. There is no honesty in such dealing, unless a woman should be made an ass and a beast, to bear every knave's wrong.

stabbed hurt financially / penetrated sexually 

house inn / vagina 

weapon sword / penis 

foin thrust 

close with fight / embrace sexually 

fist punch / masturbate 

come advance / orgasm

vice grip 

undone ruined financially / sexually, in terms of reputation 

going departure / sexual activity 

infinitive i.e. infinite, huge

thing item / penis

score tavern bill, accounts / vagina 

Pie-corner area in London famous for cooks' shops, saddlers and prostitution ('pie' and 'corner' were both slang terms for the vagina )

manhoods honours / penises

saddle horse's saddle / whore 

indited i.e. invited 

exion action / vagina

case lawsuit / vagina

hundred mark £66 / large penis

borne been patient / borne the weight of a man during sex 

fubbed off fobbed off / fucked

dealing behaviour / sexual activity 

wrong wrongdoing / shaming penis / illegitimate child

From All's Well That Ends Well, Act 1, Scene 1

PAROLLES: … Your date is better in your pie and your porridge than in your cheek. And your virginity, your old virginity, is like one of our French withered pears: it looks ill, it eats dryly.

date fruit / age / penis 

pie plays on the sense of 'vagina'

porridge plays on the sense of 'vagina' 

cheek i.e. as a sign of age

French withered pears old fruits / syphilitic vaginas

eats dryly tastes dry

From Romeo and Juliet, Act 2, Scene 3

MERCUTIO: Thy wit is a very bitter sweeting: it is a most sharp sauce.

ROMEO: And is it not then well served into a sweet goose?

MERCUTIO: O here's a wit of cheverel, that stretches from an inch narrow to an ell broad!

sweeting sweet apple

sharp sauce biting riposte / bitter sauce for food

And … goose? alludes to the proverb 'sweet meat must have sour sauce', suggesting that the sauce (semen) is being served sexually to the goose (prostitute) 

wit plays on the sense of 'penis' 

cheverel easily stretched leather

ell forty-five inches / penis

From The Life of King Henry VIII, Act 2, Scene 3

OLD LADY: 'Tis strange: a threepence bowed would hire me, 
Old as I am, to queen it: but, I pray you, 
What think you of a duchess? Have you limbs 
To bear that load of title?

ANNE: No, in truth.

OLD LADY: Then you are weakly made: pluck off a little: 
I would not be a young count in your way, 
For more than blushing comes to…

bowed bent, worthless / puns on 'bawd ' 

queen it play the queen / be a prostitute ('quean') 

bear … title endure the title of duchess / support the weight of the duke during sex / receive the duke's semen / give birth to the duke's child

pluck off come down (in aspiration; literally 'undress') 

count i.e. lower than a duke; puns on 'cunt'

way path/condition (of being a virgin)