SB 7.13.40

kvacic chaye dharopasthe
 tṛṇa-parṇāśma-bhasmasu
kvacit prāsāda-paryaṅke
 kaśipau vā parecchayā
Word for word: 
kvacit — sometimes; śaye — I lie down; dhara-upasthe — on the surface of the earth; tṛṇa — on grass; parṇa — leaves; aśma — stone; bhasmasu — or a pile of ashes; kvacit — sometimes; prāsāda — in palaces; paryaṅke — on a first-class bedstead; kaśipau — on a pillow; — either; para — of another; icchayā — by the wish.
Translation: 
Sometimes I lie on the surface of the earth, sometimes on leaves, grass or stone, sometimes on a pile of ashes, or sometimes, by the will of others, in a palace on a first-class bed with pillows.
Purport: 

The learned brāhmaṇa’s description indicates different types of births, for one lies down according to one’s body. Sometimes one takes birth as an animal and sometimes as a king. When he takes birth as an animal he must lie down on the ground, and when he takes birth as a king or a very rich man he is allowed to lie in first-class rooms in huge palaces decorated with beds and other furniture. Such facilities are not available, however, at the sweet will of the living entity; rather, they are available by the supreme will (parecchayā), or by the arrangement of māyā. As stated in Bhagavad-gītā (18.61):

īśvaraḥ sarva-bhūtānāṁ
 hṛd-deśe ’rjuna tiṣṭhati
bhrāmayan sarva-bhūtāni
 yantrārūḍhāni māyayā

“The Supreme Lord is situated in everyone’s heart, O Arjuna, and is directing the wanderings of all living entities, who are seated as on a machine, made of the material energy.” The living entity, according to his material desires, receives different types of bodies, which are nothing but machines offered by material nature according to the order of the Supreme Personality of Godhead. By the will of the Supreme, one must take different bodies with different means for lying down.