The iconography of Ayyappan depicts him as a young handsome celibate (Brahmachari) sitting in a yogic posture, as an epitome of Dharma, who wears a bell around his neck.
Ayyapa is considered to be the union of Mohini (Vishnu) and Shiva. Born of two men, to vanquish the Buffalo demoness Mahishi, who was un-defeatable by anyone born of a man and woman. He was raised by a childless royal couple Rajashekara pandiyan and Koperundevi, and grows up as a warrior yogi champion of ethical and dharmic living.
The most prominent Ayyappan shrine is at Sabarimala, nestled in the hills of Pathanamthitta of Kerala. The shrine receives millions of pilgrims every year in late December and early January, many of whom prepare for weeks before and then climb the hill barefoot. He remains one of the few Deities in Hindu tradition, who is worshipped by all religious communities, including Muslims and Christians in Kerala.
Ayyappa is depicted sitting in an uncomfortable position, balancing on his feet and not really sitting on the throne. This shows the severity of his ascetic devotion. The band of cloth across Ayyappa's legs are called yogapatta. These are essentially used to immobalize his legs in that particular squatting posture. The belt Ayyappan wears signifies the territory of the observance. So instead of getting in the lying posture (totally inactive) in which we cannot experience anything (samadhi), it is best for experience to be in this conscious and aware state. 
In Hindu iconography the left thigh is usually reserved for the consort to sit over and the right thigh for the children. Ayyappa is revered as the celibate bachelor God in Hinduism. Folding both thighs indicates that there is no place for a consort.
His hands show two mudras, chinmudra (aka jnyanamudra) and abhayamudra. Chinmudra indicate that Ayyappa has attained union with the universal consciousness while abhayamudra is a gesture of reassurance and safety.