Wendy - i think its up to yourself what you think 'feels' right but also its important what you think is right for the 'audience'. I assume you've read twilight? there is almost no physical intimacy in that novel - yet many people see it as a sort of teen porn (i don't know how they see it that way - they barely kiss)
So, in my opinion i would be all suggestion and leave the rest to the imagination. Melissa Marr in wicked lovely had her two main characters have sex - she hinted and then faded to black. Others go into more detail, it depends really on the author and their thoughts on the audience imo.