Some common terms are:
Bareback = sex without a condom
BBBJ = Bare Back Blow Job = Blow Job without condom
BBW = Big Beautiful Woman
BJ = Blow Job (oral sex on him)
BLS = Ball Licking and Sucking
BS = BodySlide = Girl massages you with her body
BTW = By the way
Cowgirl = girl on top
DATY = Dining At The Y = Cunnilingus (oral sex on her)
Doggie style = man behind girl, penis in vagina
French = oral sex
French Kissing = kissing on mouth with tongue contact
FS = Full Service = Intercourse
GFE = Girl Friend Experience, providing aspects of social and physical interaction beyond the act itself.
Greek = anal sex
GS = Golden Shower = Urinating on or being urinated on
Half & Half = oral sex and intercourse
HJ = Hand Job
HM = High Mileage
IMHO = In my humble opinion
IMO = In my opinion
Incall = you meet the girl at her place
ISO = In Search Of
LE = Law Enforcement
LF = Lady Friend
LOL = Laugh Out Loud
Missionary = man on top
MP = Massage Parlor
MSOG = Multiple Shots on Goal
N = nude (the girl that is)
NR = Nude Reverse = nude with reverse massage
Outcall = the girl comes to your place---your home, your hotel, etc.
Pearls = Pearl Necklace = ejaculation on her upper breasts
Reverse = You get to massage girl
Rimjob = analingus
Russian = penis between girl's breasts
SOG = Shots On Goal" = number of times you release
SP = Service Provider
T = topless
Tea Bagging - Squatting over your lady and dipping your balls in her mouth.
TV = transvestite
YMMV = Your Mileage May Vary