To have sex or sexual activity with the opposite sex. Usually requires penetration. Foreplay, hand job, blow job, even anal doesn't count.
To complete the task of sexula penetration with the penis into the vagina.
I took her out to a nice dinner, cost me an ass load and she wouldn't let me execute at the end of the night. She just closed her legs!!
I got a hand job last night, but couldn't execute. She wasn't ready for me yet.