Lying there after being seeded is great. It allows the cum to be soaked in. When my buddies and I fucked, I would try to stay in one place and keep their cum in me. Some would eventually cum out, but not before the absorption of their DNA was imprinted in me. After I seeded them, they usually got up and let it drop out right away. We didn't know anything about the imprinting, but it felt right to carry their seed for as long as I could.