I think the romantic brushing of the foreheads is so intimate. I love the whole scene. It just demonstrates the depth of the bond they have with each other. It's like, once Garrus is able to take a deep breath and get over his awkwardness, he really realizes that he deeply cares about this person, and Shep feels the same. Others might be more 'sexy,' but I think Garrus and Fem!Shep are def the most romantic. Just had to gush with everyone else about how great this scene is.