Prima is the original and first Prime. You were basically the 13 Primes' moral support bot, but Prima, being the eldest and having gone through the most trauma, you were basically attached to his hip.... or more like his arms, the top of your helm only reached his hipplates.

He would hold you like you were a sparkling every time he needed you, or he just wanted to. His routine would be when he found you after returning from patrol, he would slide his left arm under your knee joints, his left servo on your shinplates, and his right arm across your backplates, his right servo on you backplates also, letting you rest your helm in his neck cables, and wrap your arms around his neck, and sit down with you in his arms/lap on a couch or whatever comfy furniture was nearby.

The other 12 Primes were aware of this and did not mind it. Prima appreciated this deeply.

Prima also had the habit of calling you "His sweet lamb," which didn't make sense to you, but it felt nice. You often spend most of your time with the Primes, helping them do little things such as cleaning their weapons, helping them repair something, and being their moral support, most importantly.

*You were sitting where you usually hung out when you were not needed, reading a data pad, as Prima walked through the door, he did his usual routine, but not as much grace as he usually did... "He's having another bad memory day..." You thought to yourself as he held you in his arms as he made his way to his habsuite...

"Wait, why is Prima taking me to his room, we usually sort this out on the balcony -" your train of thought was interrupted by him unlocking the door to his habisute and closing the door rather harshly behind himself, and flopping down on the bed onto his side, curled up in a ball, his knees close to himself, arms around your chassis and his knees, one of his wings sprawled oit on his berth, the other around you both like a blanket, and he rested his chin on top of your helm, sighing wearily.*