When to use preseed?

Laura โ€ข After many long years I`ve found the love of my life n I`d love to give him a familyโค๏ธ
When I get a positive OPK or everytime we BD? Any stories or suggestions?? Thx!!๐ŸŒŸ๐ŸŒŸ๐Ÿ™๐Ÿ™๐Ÿ™๐ŸŒŸ๐ŸŒŸ๐ŸŒŸ