Green’s Dictionary of Slang

1. sealing wax.

1858		A. Mayhew Paved with Gold 267: One, who hawked ‘kite’ and ‘sticky’ (paper and wax) as an excuse for begging, was telling another, who was a cadger, which were the best houses to go to.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 217/2: I give below a vocabulary of their talk to each other: [...] Sticky .... Wax.
1873		Sl. Dict.

2. sticking plaster.

1937–84		Partridge DSUE (1984) 1154/2: late C.19–20.
1966		I. Jefferies House-Surgeon 154: Bring me some more sticky and that pint of blood in the fridge [OED].

3. a sticky bun.

1984

Partridge DSUE (8th edn) 1154/2: since the 1920s.

4. sticky tape.

1984

Partridge DSUE (8th edn) 1154/2: since late 1940s.

5. (US gay) semen.

1972

B. Rodgers Queens’ Vernacular.