Hi honey,
If you feel up to it go for it. They do move your cervix around from the inside so it can be a bit tender in there, and also they pump CO2 into the belly so it can give you a bit of shoulder tip pain and pain. I think that it is more likely that you may not feel like it rather than you can't, there is no reason as the egg and sperm meet in the tubes for you not to go ahead... but don't be too tough on yourself if you don't feel like it. That can be the tricky bit.
I am so aware at the mo of what a rough trot you are having at the moment. Having period after unwanted period is shattering, so I am pleased that you are seeing someone and getting the best possible advice. I really really am crossing my fingers and toes for you. I hope that the lap is all clear. Are you having a dye test at the mo too, where they check out the tubes as well? If there is no endo it would be good to check the fill and make sure all is ok. I think that you could check with the doctor preop about when to assume sexual relations (god thats so clinton isn't it!!!!!)
They say the lap and hsg increases pregnancy chances!!!!!!!!!!!! I get the despair and the month after month grinding down of hopes. This is a step towards getting it sorted and I am so proud of you for taking a hard but important step into taking control of your fertility!