Olfactophilia or osmolagnia is a paraphilia

Paraphilia

Paraphilia is a biomedical term used to describe sexual arousal to objects, situations, or individuals that are not part of normative stimulation and that may cause distress or serious problems for the paraphiliac or persons associated with him or her...

 for, and sexual attraction

Sexual attraction

Sexual attractiveness or sex appeal refers to an individual's ability to attract the sexual or erotic interest of another person, and is a factor in sexual selection or mate choice. The attraction can be to the physical or other qualities or traits of a person, or to such qualities in the context...

 to, or sexual arousal

Sexual arousal

Sexual arousal, or sexual excitement, is the arousal of sexual desire, during or in anticipation of sexual activity. Things that precipitate human sexual arousal are called erotic stimuli, or colloquially known as turn-ons. There are many potential stimuli, both physical or mental, which can cause...

 by smells and odors emanating from the body, especially the sexual areas. Etymologies: olfactophilia (Latin=olfacto, to smell, pertaining to the sense of smell, and philia, love); osmolagnia (Greek=osme, smell, and lagneia, lust).

Sigmund Freud

Sigmund Freud

Sigmund Freud , born Sigismund Schlomo Freud , was an Austrian neurologist who founded the discipline of psychoanalysis...

  used the term osphresiolagnia in reference to pleasure caused by odors.

Campbell's Psychiatric Dictionary includes them into parosmia

Parosmia

Parosmia, also known as troposmia or cacosmia, is an olfactory dysfunction that is characterized by the inability of the brain to properly identify an odor’s “natural” smell....

s, disturbances of the sense of smell.