Baby dancing

So me and my husband have been BD like there is no tomorrow and he has told me once we have finished having sex to lay on my back with my legs up for like 10-20 mins  (not sure if this is a myth or not) but when I get up seman seems to be coming out does that mean there's a problem ? This is our first month of TTC we have been married for 16 months & I am 25 in good health and he is 29 smokes 1 cigarette a day.