Sansa: My dear Mother of Dragons, my sister has been captured by Cersie and we need to march on King's landing at once.
Daenerys : I agree, Jon is also shattered by the news. But before going into battle I need to re-energise and I am afraid there is only one way, in such little time.
Sansa: You are in the north, we will do anything for you.
Daenerys : I am afraid it is not that easy. You need to have sex with me and my trusted guard and we cannot let Jon know about this.