Even though our ds is almost 8 months old, he is still a bit of a peanut, so we just strap his infant car seat into our trailer with bungee cords. We've been out with him like this since he was 3 months old and he loves it! We have the tag along bikes for our older kids, so our dd is behind my bike; our older ds is behind his Dad and our baby ds is in the trailer behind his brother. We make quite the train when we go for a ride!