A Terrible Idea I got from reading the second to last line in chapter 10 of "Harry Potter and the Sword of Gryffindor". And yes I considered entitling this Stallion Seduction.
Horse Throat.
The first time Potter suggested 'it' Lily Evans was horrified, the second time he suggested 'it' she punched him in the face, before blushing and turning away. The third time he approached the subject from a slightly different manner, she wondered briefly before slapping him. The forth time she considered 'it'. The fifth she fantasised. It took her till the sixth to consider 'it' and the seventh to approach it. But after trying 'it' she knew even from her sore throat that it had been worth it entirely and besides if having the tip of 'it' down her throat had felt that good, then how would half of it feel in her?
Many Years from the day she first tried 'it' Lily Potter would look back and thank Merlin that her now-husband had tried a chat-up line based on his animagus form.