I was also told that the man should be abstinent 2 to 5 days prior to an IUI or IVF.
I agree with them you should wait until after your second iui and bd that night!
good luck!!!!
it's actually recommended that you do have sex the night of the 2nd IUI because it increases your chances of success.
Sperm quality is better of your dh abstains for at least 24 hours. So, you can back it up tomorrow night.
Good luck!!!