I think you can have gentle intercourse after a tummy tuck as soon as you are comfortable with this. Usually, the swelling has subsided enough by about 10 days that you can go ahead with this. It should definitely be understood before trying this, that the person with the tummy tuck is in charge and activities should be halted if there is discomfort.
Congratulations on having undergone the tummy tuck procedure. Your plastic surgeon will be your best resource when it comes to specific information/advice. He/she knows exactly what was done and how you are progressing. Concerns would include an increase in heart rate and the potential for bleeding. Muscle spasm may be painful. Obviously, significant pressure on the surgical site is not a good idea either. It is not uncommon for patients to report increased swelling that occurs after vigorous exercise (including sexual activity), even several months after tummy tuck surgery. Having said that, assuming some creativity and gentleness, you will likely be able to proceed about one month after surgery.I hope this helps.