Sex at 35 weeks?

Polly
My placenta was slightly prevaia so we could not have sex for 3 months. At last week's scan we have been told the placenta has moved up and no longer prevaia, yay! So I want to try sex again....any tips on comfortable positions? I feel nervous as we haven't done it yet with a big belly and sounds silly but I think her head is low down and don't want to hurt her!