This paper presents the design and prototype of a soft robotic device to rehabilitate the sucking capacities of preterm neonates. The soft robot utilizes elastomeric pneumatic actuators, capable of exerting gentle pressure and torsional stimuli on neonates' sucking muscles - which are two of the key features of the current treatment performed by medical specialists, in order to strengthen the muscles involved in the feeding process. Two soft actuators (as thin as possible) were designed and tested. One based on a zero-air chamber, and another based on a flexible spiral structure, with the ability to generate a torsional movement when pressurized. At 10 kPa of air pressure, the spiral-based actuator demonstrated a maximum force of about 3 N, and a perpendicular and angular displacement of about 10 mm and 80°, respectively. Furthermore, the elastomers utilized make the device comfortable, flexible, and easy-to-sterilize. In addition, a monitoring device works simultaneously to measure the intraoral pressure of the infant, as a feedback signal to closed-loop control the soft actuators. The soft robotic system was tested on a baby phantom as a proof of concept. This device could pave the way to the rehabilitation of preterm neonates with feeding disorders.